A method for determining the flight trajectory parameters of a lunar probe

Abstract

This invention provides a method for determining the flight trajectory parameters of a lunar probe. Addressing the parameter design requirements of various segments of the lunar probe's flight trajectory from Earth to the Moon, an integrated joint design method for trajectory parameters is proposed. The overall design process includes a three-layer iterative calculation flow: the inner layer iterates the corresponding parameters of the lunar orbit to achieve a precise landing point on the lunar surface; the second layer iterates the lunar orbit inclination angle to ensure precise lunar surface working time; and the outer layer iterates the launch trajectory, Earth-Moon transfer orbit, and lunar orbit parameters. Ultimately, this achieves seamless connection between the various flight trajectories of the lunar probe from Earth to lunar landing.

Description

Technical Field

[0001] This invention relates to the field of probe orbit design technology, and more particularly to a method for determining the flight orbit parameters of a lunar probe. Background Technology

[0002] China's Lunar Exploration Program (also known as the Chang'e Program) is a lunar exploration program implemented by China. As of 2024, the Chang'e 6 probe has achieved the successful launch from Earth, precise landing on the far side of the moon, and return to Earth.

[0003] For lunar probes, exemplified by the Chang'e probe, the process of launching from Earth to the Moon is quite complex. The general process is roughly as follows: First, a launch vehicle (such as a high-thrust rocket) carrying the probe is launched from a launch site on Earth, flying to the end of its launch trajectory and entering a lunar transfer orbit. Then, the lunar probe flies in the lunar transfer orbit until it reaches the vicinity of the Moon, where it decelerates through lunar braking and is captured by the Moon's gravity to enter a lunar orbit. Finally, in the lunar orbit, through a series of orbital maneuvers including circularization, descent, and powered descent, it finally lands at the predetermined landing site on the lunar surface. Because the launch site location, the lunar landing site location, and some parameters of the lunar probe's flight trajectory are constrained, and because there are complex coupling relationships between the parameters of each segment of the flight trajectory, how to jointly design the various segments of the lunar probe's flight trajectory to ensure the successful completion of its mission to the Moon is an extremely complex problem. Summary of the Invention

[0004] This invention provides a method for determining the flight trajectory parameters of a lunar probe, thereby providing a scheme for determining the flight trajectory parameters of a lunar probe that flies from Earth to land on the Moon.

[0005] This invention provides a method for determining the flight trajectory parameters of a lunar probe, comprising: The undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters are determined based on the first undetermined value of the lunar orbit inclination angle, and the first undetermined value of the lunar orbit inclination angle is set as the second undetermined value of the lunar orbit inclination angle; Based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the lunar orbit inclination angle, the undetermined values ​​of the lunar orbit parameters, excluding the undetermined value of the first orbital period, are determined; wherein, the first lunar orbit is the orbit in the lunar orbit that connects with the Earth-Moon transfer orbit; The undetermined value of the lunar landing point position is determined based on the undetermined value of the lunar orbit parameters, and the landing point deviation requirement is judged based on the undetermined value of the lunar landing point position and the target value of the lunar landing point position. If the landing point deviation requirement is not met, the first orbital period expectation value is adjusted, and the process returns to the step of determining the lunar orbital parameter expectation values ​​other than the first orbital period expectation value based on the lunar transfer orbit parameter expectation values, the first lunar orbital period expectation value, and the second lunar orbital inclination expectation value; if the landing point deviation requirement is met, the lunar surface working time expectation value is determined based on the lunar orbital parameter expectation values, and the lunar surface working time expectation value and the lunar surface working time target value are used to determine whether the lunar surface working time deviation requirement is met; If the lunar surface working time deviation requirement is not met, the second undetermined value of the lunar orbit inclination is adjusted, and the process returns to the step of determining the undetermined values ​​of the lunar orbit parameters other than the first undetermined value of the orbital period based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the first undetermined value of the orbital period of the first lunar orbit, and the second undetermined value of the lunar orbit inclination; if the lunar surface working time deviation requirement is met, the difference between the current first undetermined value of the lunar orbit inclination and the current second undetermined value of the lunar orbit inclination is used to determine whether the lunar orbit inclination convergence requirement is met. If the lunar orbit inclination convergence requirement is not met, the first undetermined value of the lunar orbit inclination is adjusted, and the process returns to the step of determining the undetermined values ​​of the Earth-Moon transfer orbit parameters and the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination; if the lunar orbit inclination convergence requirement is met, the current undetermined values ​​of each parameter, except for the lunar surface working time, are determined as the corresponding target values.

[0006] Optionally, the initial lunar orbit inclination angle is determined based on the target value of the lunar landing point location of the lunar probe and the target value of the lunar probe's lunar surface working time.

[0007] Optionally, the Earth-Moon transfer orbit parameters include the probe entry time of the lunar probe into the Earth-Moon transfer orbit and the probe entry orbit parameters of the lunar probe into the Earth-Moon transfer orbit; wherein, the probe entry orbit parameters include the probe entry orbit inclination, the probe entry orbit perigee argument, the probe entry orbit ascending node longitude, and the probe entry orbit true perigee angle; The launch trajectory parameters include the launch time of the launch vehicle, the launch azimuth angle of the launch vehicle, and the launch trajectory flight time of the launch vehicle to launch the detector. The process of determining the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination angle includes: Obtain the initial, undetermined probe insertion time; Based on the preset correspondence between the probe's orbit insertion time, the design target of the Earth-Moon transfer orbit, and the probe's orbit insertion parameters, the undetermined values ​​of the probe's orbit insertion parameters corresponding to the undetermined value of the probe's orbit insertion time are determined; wherein, the design target of the lunar orbit inclination angle in the design target of the Earth-Moon transfer orbit is the first undetermined value of the lunar orbit inclination angle; it is determined whether the undetermined value of the longitude of the ascending node of the probe's orbit insertion meets the preset range of longitude of the ascending node of the launch vehicle's orbit insertion. If the undetermined longitude of the ascending node of the probe's orbit does not meet the longitude range of the ascending node of the launch vehicle's orbit, then the undetermined value of the probe's orbit entry time is adjusted, and the step of determining the undetermined value of the probe's orbit entry parameters corresponding to the undetermined value of the probe's orbit entry time is returned based on the preset correspondence between the probe's orbit entry time and the probe's orbit entry parameters. If the undetermined longitude of the ascending node of the probe's entry orbit meets the preset range of the ascending node longitude of the launch vehicle's entry orbit, then the range of undetermined values ​​of the launch vehicle's entry orbit inclination angle to which the undetermined value of the probe's entry orbit inclination angle belongs is determined according to the preset set of launch vehicle entry orbit inclination angles. Based on the preset correspondence between the launch vehicle's entry trajectory inclination angle and the launch vehicle's gliding trajectory time, the undetermined range of values ​​for the launch vehicle's gliding trajectory time corresponding to the undetermined range of values ​​for the launch vehicle's entry trajectory inclination angle is determined. Based on the preset correspondence between the perigee argument of the launch vehicle's entry trajectory and the launch vehicle's taxiing trajectory time, the range of undetermined values ​​for the perigee argument of the launch vehicle's entry trajectory corresponding to the undetermined range of values ​​for the launch vehicle's taxiing trajectory time is determined. Determine whether the undetermined value of the perigee angle of the probe's orbital insertion is within the range of undetermined values ​​for the perigee angle of the launch vehicle's orbital insertion; if the undetermined value of the perigee angle of the probe's orbital insertion is not within the range of undetermined values ​​for the perigee angle of the launch vehicle's orbital insertion, then adjust the undetermined value of the probe's orbital insertion time, and return to the step of determining the undetermined value of the probe's orbital parameters corresponding to the undetermined value of the probe's orbital insertion time based on the preset correspondence between the probe's orbital insertion time and the probe's orbital parameters. If the undetermined value of the perigee angle of the probe's orbital entry is within the range of the undetermined value of the perigee angle of the launch vehicle's orbital entry, then the undetermined value of the launch vehicle's orbital trajectory time is determined based on the range of the undetermined value of the perigee angle of the launch vehicle's orbital entry, the range of the undetermined value of the launch vehicle's gliding trajectory time, and the undetermined value of the perigee angle of the probe's orbital entry. The longitude of the ascending node of the launch vehicle's entry track is determined based on the undetermined range of the launch vehicle's inclination angle, the undetermined range of the launch vehicle's gliding trajectory time, and the undetermined value of the launch vehicle's gliding trajectory time. Based on the preset correspondence between the longitude of the ascending node and the orbit insertion time, the orbit insertion time deviation value is determined according to the undetermined longitude of the ascending node of the probe's orbit insertion trajectory and the undetermined longitude of the ascending node of the launch vehicle's orbit insertion trajectory; wherein, the orbit insertion time deviation value is the difference between the undetermined orbit insertion time value of the probe corresponding to the undetermined longitude of the ascending node of the probe's orbit insertion trajectory and the undetermined orbit insertion time value of the launch vehicle corresponding to the undetermined longitude of the ascending node of the launch vehicle's orbit insertion trajectory. Determine whether the orbit insertion time deviation is less than a set deviation threshold; if not, adjust the undetermined value of the probe orbit insertion time and return to the step of determining the undetermined value of the probe orbit insertion parameters corresponding to the undetermined value of the probe orbit insertion time based on the preset correspondence between the probe orbit insertion time and the probe orbit insertion trajectory parameters; if satisfied, determine the undetermined value of the launch vehicle trajectory flight time based on the preset correspondence between the launch vehicle orbit insertion trajectory inclination angle and the launch vehicle ballistic flight time, according to the undetermined value of the probe orbit insertion trajectory inclination angle, the undetermined value range of the launch vehicle orbit insertion trajectory inclination angle, the undetermined value of the launch vehicle gliding trajectory time, and the value range of the launch vehicle gliding trajectory time. The launch time of the launch vehicle is determined based on the undetermined value of the launch vehicle's ballistic flight time and the undetermined value of the probe's orbital insertion time. Based on the preset correspondence between the launch azimuth angle of the launch vehicle, the inclination angle of the launch vehicle's orbital entry, and the time of the launch vehicle's gliding trajectory, the undetermined value of the launch azimuth angle of the launch vehicle is determined according to the undetermined value of the probe's orbital entry inclination angle, the undetermined range of the launch vehicle's orbital entry inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time. Based on the preset correspondence between the probe's true perimeter angle, the launch vehicle's inclination angle, and the launch vehicle's gliding trajectory time, the undetermined value of the probe's true perimeter angle is determined according to the undetermined value of the probe's inclination angle, the undetermined range of the launch vehicle's inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time.

[0008] Optionally, the lunar orbit includes, in sequence, a first lunar orbit, a second lunar orbit, a third lunar orbit, and a fourth lunar orbit; The first lunar orbit parameters include the shape parameters of the first lunar orbit and the first lunar flight control parameters for the lunar probe when switching from the Earth-Moon transfer orbit to the first lunar orbit. The second lunar orbit parameters include: the shape parameters of the second orbit change segment, the corresponding lunar second flight control parameters for the second orbit change segment, and the shape parameters of the second circular segment. The parameters of the third lunar orbit include: the shape parameters of the third orbit change segment, the corresponding lunar third flight control parameters of the third orbit change segment, and the shape parameters of the third circular segment. The step of determining the undetermined values ​​of lunar orbit parameters, excluding the undetermined value of the first orbital period, based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the second lunar orbital inclination, includes: Based on the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined value of the first orbital period of the first lunar orbit, determine the undetermined values ​​of the shape parameters of the first lunar orbit, excluding the undetermined value of the first orbital period. The undetermined values ​​of the first lunar orbit shape parameters are determined based on the undetermined values ​​of the first lunar orbital shape parameters. Based on the undetermined values ​​of the first lunar orbit parameters and the target values ​​of the second lunar orbit constraint parameters, the undetermined values ​​of the shape parameters of the second orbit change segment are determined, and based on the undetermined values ​​of the shape parameters of the second orbit change segment, the undetermined values ​​of the second lunar flight control parameters and the undetermined values ​​of the shape parameters of the second circular segment are determined. The undetermined values ​​of the second lunar orbit parameters and the target values ​​of the third lunar orbit constraint parameters are determined based on the undetermined values ​​of the shape parameters of the third orbit change segment. The undetermined values ​​of the third lunar orbit flight control parameters and the undetermined values ​​of the shape parameters of the third orbit change segment are then determined based on the undetermined values ​​of the shape parameters of the third orbit change segment. The undetermined value of the fourth lunar orbit parameter is determined based on the second undetermined value of the lunar orbit inclination angle, the target value of the lunar landing point position, the target value of the powered descent orbit parameter, the target value of the fourth lunar orbit constraint parameter, and the undetermined value of the third lunar orbit parameter. Among them, the second lunar orbit constraint parameters are some of the pre-selected parameters from the second lunar orbit parameters, the third lunar orbit constraint parameters are some of the pre-selected parameters from the third lunar orbit parameters, and the fourth lunar orbit constraint parameters are some of the pre-selected parameters from the fourth lunar orbit parameters.

[0009] Optionally, adjusting the first orbital period preset value if the landing point deviation requirement is not met includes: The undetermined value of the lunar landing point position is determined based on the undetermined value of the lunar orbit parameters. The orbital period adjustment amount is determined based on the undetermined value of the lunar landing point position and the target value of the lunar landing point position. The adjusted first orbital period undetermined value is determined based on the current first orbital period undetermined value and the orbital period adjustment amount.

[0010] Optionally, determining the undetermined range of values ​​for the perigee angle of the launch vehicle's orbit based on the preset correspondence between the perigee angle of the launch vehicle's orbital insertion and the launch vehicle's taxiing trajectory time includes: The perigee argument trajectory matrix is ​​obtained. The perigee argument trajectory matrix is ​​determined based on multiple sets of first launch vehicle orbit parameters. The first launch vehicle orbit parameters include the launch vehicle orbit inclination, the launch vehicle glide trajectory time, and the launch vehicle orbit perigee argument. The launch vehicle orbit corresponding to the first launch vehicle orbit parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the perigee argument trajectory matrix, a grid interpolation method is used to process each launch vehicle's taxiing trajectory time value within the undetermined range of the launch vehicle's taxiing trajectory time, thereby determining the undetermined range of the perigee argument of the launch vehicle's orbital insertion trajectory corresponding to the undetermined range of the launch vehicle's taxiing trajectory time.

[0011] Optionally, determining the undetermined value of the longitude of the ascending node of the launch vehicle's orbit based on the undetermined range of the launch vehicle's orbital inclination angle, the undetermined range of the launch vehicle's taxiing trajectory time, and the undetermined value of the launch vehicle's taxiing trajectory time includes: The ascending node trajectory matrix is ​​obtained, which is determined based on multiple sets of second launch vehicle orbital parameters. The second launch vehicle orbital parameters include the launch vehicle orbital inclination, the launch vehicle glide trajectory time, and the ascending node longitude of the launch vehicle orbital. The launch vehicle orbital corresponding to the second launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the ascending node trajectory matrix, the longitude of the ascending node of the launch vehicle's entry trajectory is determined using a grid interpolation method according to the range of the launch vehicle's orbital inclination angle, the range of the launch vehicle's taxiing trajectory time, and the undetermined value of the launch vehicle's taxiing trajectory time.

[0012] Optionally, the step of determining the undetermined value of the launch vehicle's ballistic flight time based on the preset correspondence between the launch vehicle's orbital inclination angle and the launch vehicle's ballistic flight time, according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time, includes: The launch vehicle's ballistic flight time trajectory matrix for launching the lunar probe is obtained. This ballistic flight time trajectory matrix is ​​determined based on multiple sets of third launch vehicle orbital parameters, which include the launch vehicle's orbital inclination, the launch vehicle's glide trajectory time, and the launch vehicle's ballistic flight time. The launch vehicle's orbital trajectory corresponding to these third launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit corresponding to the lunar probe. Based on the launch vehicle's ballistic flight time trajectory matrix, the undetermined value of the launch vehicle's ballistic flight time is determined using a grid interpolation method according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's taxiing trajectory time, and the range of the launch vehicle's taxiing trajectory time.

[0013] Optionally, the step of determining the undetermined launch azimuth angle based on the preset correspondence among the launch vehicle launch azimuth angle, the launch vehicle orbit inclination angle, and the launch vehicle coasting trajectory time, according to the undetermined value of the probe orbit inclination angle, the undetermined range of the launch vehicle orbit inclination angle, the undetermined value of the launch vehicle coasting trajectory time, and the range of the launch vehicle coasting trajectory time, includes: The launch azimuth trajectory matrix of the launch vehicle is obtained. The launch azimuth trajectory matrix of the launch vehicle is determined based on multiple sets of fourth launch vehicle orbital parameters. The fourth launch vehicle orbital parameters include the launch vehicle orbital inclination, the launch vehicle glide trajectory time, and the launch vehicle launch azimuth. The launch vehicle orbital corresponding to the fourth launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the launch vehicle launch azimuth trajectory matrix, the undetermined launch azimuth is determined using a grid interpolation method according to the undetermined value of the probe's orbital inclination, the undetermined range of the launch vehicle's orbital inclination, the undetermined value of the launch vehicle's coasting trajectory time, and the range of the launch vehicle's coasting trajectory time.

[0014] Optionally, the step of determining the undetermined value of the true anomaly angle of the launch vehicle's orbit based on the preset correspondence among the launch vehicle's true anomaly angle, the launch vehicle's orbital inclination angle, and the launch vehicle's coasting trajectory time, according to the undetermined value of the probe's orbital inclination angle, the undetermined value range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's coasting trajectory time, and the value range of the launch vehicle's coasting trajectory time, includes: The true anomaly trajectory matrix of the launch vehicle's orbital insertion is obtained. This true anomaly trajectory matrix is ​​determined based on multiple sets of fifth launch vehicle orbital parameters. The fifth launch vehicle orbital parameters include the launch vehicle orbital inclination, the launch vehicle's gliding trajectory time, and the true anomaly angle of the launch vehicle orbital insertion. The launch vehicle orbital corresponding to the fifth launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the true perimeter trajectory matrix of the launch vehicle's entry trajectory, the undetermined value of the true perimeter of the launch vehicle's entry trajectory is determined using a grid interpolation method according to the undetermined value of the probe's entry trajectory inclination, the undetermined range of the launch vehicle's entry trajectory inclination, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time.

[0015] The beneficial effects of this invention are as follows: This invention provides a method for determining the flight trajectory parameters of a lunar probe. Addressing the parameter design requirements of various segments of the lunar probe's flight trajectory from Earth to the Moon, it proposes an integrated joint design method for trajectory parameters. The overall design process includes a three-layer iterative calculation flow: the inner layer iterates the corresponding parameters of the lunar orbit to achieve a precise landing point on the lunar surface; the second layer iterates the lunar orbit inclination angle to ensure precise lunar surface working time; and the outer layer iterates the launch trajectory, Earth-Moon transfer orbit, and lunar orbit parameters. Ultimately, this achieves seamless connection between the various flight trajectories of the lunar probe from Earth to lunar landing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the grid interpolation method involved in the embodiments of the present invention. Figure 2 A flowchart illustrating the method for determining the flight trajectory parameters of a lunar probe according to an embodiment of the present invention; Figure 3 This is one of the flowcharts of a method for determining the flight trajectory parameters of a lunar probe provided in an embodiment of the present invention; Figure 4 The second part of the flowchart of the method for determining the flight trajectory parameters of a lunar probe provided in the embodiments of the present invention; Figure 5 The third part of the flowchart of the method for determining the flight trajectory parameters of a lunar probe provided in the embodiments of the present invention; Figure 6 This is a schematic diagram of the structure of the lunar probe flight trajectory parameter determination device provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction in the present invention are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of the present invention. The accompanying drawings of the present invention are for illustrative purposes only and do not represent actual proportions.

[0018] It should be noted that specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. The following description is a preferred embodiment for carrying out the present application; however, the description is for the purpose of illustrating the general principles of the application and is not intended to limit the scope of the application. The scope of protection of this application shall be determined by the appended claims.

[0019] The following description, in conjunction with the accompanying drawings, details a method for determining the flight trajectory parameters of a lunar probe according to an embodiment of the present invention.

[0020] Before formally introducing the technical solutions of the embodiments of the present invention, the grid interpolation method, which will be used many times in the following text, will be introduced first: Suppose the problem involves independent variables that include parameters in two dimensions: , (in, k , j (where the index is a digit). Therefore, the dependent variable involved in the problem can be represented as a grid matrix. Z :

[0021] In the grid matrix Z Given that the values ​​of the matrix elements are known, for elements not in the grid matrix... Z Crossing points that appeared in the game ( and / or ), corresponding dependent variable You can refer to this. Figure 1 Using grid interpolation methods, based on the grid matrix Z Middle and crossing point The dependent variable values ​​at four adjacent points determine the dependent variable value at the crossing point. . Specifically: remember , (in , ).

[0022] have:

[0023] So:

[0024] The specific technical content of the embodiments of the present invention will be described below.

[0025] Firstly, embodiments of the present invention provide a method for determining the flight trajectory parameters of a lunar probe, applicable to lunar probes traveling from Earth to land on the Moon. For example... Figure 2 As shown, the method specifically includes: S100. Determine the first undetermined value of the initial lunar orbit inclination angle based on the target value of the lunar probe's landing point location and the target value of the lunar probe's working time on the lunar surface.

[0026] In the specific implementation process, the target value of the lunar landing point location is the desired lunar landing point location of the lunar probe.

[0027] Lunar probes typically consist of an orbiter and a lander. For a round-trip lunar probe that travels from Earth to the Moon and returns to Earth, after reaching lunar orbit, the lander separates from the orbiter. The lander lands on the lunar surface, while the orbiter continues its lunar orbit. After completing its lunar surface work, the lander takes off and docks with the orbiter. To minimize fuel consumption during the docking process, the lander's lunar orbit after takeoff must be coplanar with the orbiter's lunar orbit. Therefore, in this embodiment of the invention, the lunar surface work duration is set as the optimal time interval between the lander's landing and takeoff times, assuming the lander and orbiter orbits are coplanar. Generally, based on the lunar probe's mission requirements, a target value for the lunar surface work duration is first set, and then the lunar probe's flight trajectory parameters are designed based on this target value.

[0028] Specifically, the first undetermined value of the initial lunar orbital inclination can be calculated using the following formula. :

[0029] In formula (1), This represents the target latitude value for the lunar landing site. The target value for lunar surface working hours. This is the angular velocity of the moon's rotation.

[0030] S200. Determine the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination angle, and set the first undetermined value of the lunar orbit inclination angle as the second undetermined value of the lunar orbit inclination angle.

[0031] The calculation process for the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch ballistic parameters is explained in detail below: In this embodiment of the invention, the Earth-Moon transfer orbit parameters include: the probe's entry time into the Earth-Moon transfer orbit, the probe's entry orbit parameters, the geometric parameters of the Earth-Moon transfer orbit, the flight time of the Earth-Moon transfer orbit, and the terminal position parameters of the Earth-Moon transfer orbit. Among these, the probe's entry orbit parameters include the probe's entry orbit inclination, the probe's entry orbit perigee argument, the longitude of the probe's ascending node, the probe's entry orbit true perigee angle, and the Earth-Moon transfer orbit perigee altitude. The geometric parameters of the Earth-Moon transfer orbit include the semi-major axis of the Earth-Moon transfer orbit. a eccentricity e The endpoint position parameters of the Earth-Moon transfer orbit include the lunar perigee altitude and the lunar perigee velocity. Furthermore, in this embodiment of the invention, the Earth-Moon transfer orbit parameters can be represented using either the orbital parameters of the geocentric J2000 coordinate system or the orbital parameters of the geocentric instantaneous inertial coordinate system, and can be converted between them during the calculation process.

[0032] In this embodiment of the invention, the launch trajectory parameters include: launch time of the launch vehicle, launch azimuth angle of the launch vehicle, and launch vehicle trajectory flight time of the probe. Specifically, the launch vehicle trajectory flight time of the lunar probe is the time between the launch time of the launch vehicle carrying the lunar probe and the moment of separation between the launch vehicle and the lunar probe.

[0033] like Figure 3 As shown, the calculation process specifically includes: S201. Determine the undetermined value for the probe's orbit insertion time.

[0034] In the actual implementation process, the initial probe orbit insertion time can be set randomly. To improve the iterative efficiency of subsequent calculation steps, a time can be randomly selected from the expected lunar probe launch date as the initial probe orbit insertion time.

[0035] S202. Based on the correspondence between the orbit insertion time, the design target of the Earth-Moon transfer orbit, and the orbit insertion parameters of the probe, determine the undetermined values ​​of the probe's orbit insertion parameters corresponding to the undetermined values ​​of the lunar probe's orbit insertion time.

[0036] The design objectives for the Earth-Moon transfer orbit include target values ​​for multiple parameters, such as the lunar orbit inclination, the flight time of the Earth-Moon transfer orbit, the perigee altitude of the Earth-Moon transfer orbit, the lunar perigee altitude of the Earth-Moon transfer orbit, and the orbital inclination of the probe upon entry. The target value for the lunar orbit inclination in the design objectives is set as the first undetermined value for the lunar orbit inclination.

[0037] In the specific implementation process, the correspondence between the orbit insertion time, the design target of the Earth-Moon transfer orbit, and the orbital parameters of the probe can be pre-set. That is, different orbit insertion times and Earth-Moon transfer orbit design targets correspond to different probe orbital parameters. For example, the probe orbital parameters can be the Earth-Moon transfer orbit parameters in the geocentric J2000 coordinate system determined by processing the orbit insertion time using existing Earth-Moon transfer orbit design software. The corresponding probe orbital parameters can be pre-determined based on different orbit insertion times and Earth-Moon transfer orbit design targets using the Lambert problem solution method in Earth-Moon transfer orbit design software, thereby obtaining the correspondence between the orbit insertion time and the probe orbital parameters. This calculation process is existing technology and will not be elaborated upon in this paper due to space limitations.

[0038] S203. Determine whether the undetermined longitude of the ascending node of the probe's entry orbit meets the preset range of longitude of the ascending node of the launch vehicle's entry orbit.

[0039] In the specific implementation process, the preset range of the ascending node longitude of the launch vehicle's orbit can be determined based on the maximum and minimum values ​​of the ascending node longitude in the orbital trajectory matrix. The ascending node longitude trajectory matrix can be determined based on multiple sets of launch vehicle orbital parameters. These parameters may include the launch vehicle orbital inclination, the launch vehicle's coasting trajectory time, and the ascending node longitude. Furthermore, the launch vehicle orbit corresponding to the second set of orbital parameters is aligned with the lunar probe's Earth-Moon transfer orbit.

[0040] Specifically, the longitude trajectory matrix Ω at the ascending node satisfies:

[0041] In formula (2), k , j For serial number, The first element in the longitude trajectory matrix Ω of the ascending node k The orbital inclination angle of each launch vehicle upon entry into orbit. The first element in the longitude trajectory matrix Ω of the ascending node j Each launch vehicle's glide trajectory time The first element in the longitude trajectory matrix Ω of the ascending node k The orbital inclination of the first launch vehicle is related to the first... jThe longitude of the ascending intersection point of the launch vehicle's orbit corresponding to the launch vehicle's taxiing trajectory time.

[0042] If the result of step S203 is negative, return to step S201; if the result of step S203 is positive, proceed to step S204.

[0043] If the undetermined longitude of the ascending node of the probe's orbit does not meet the preset range for the ascending node longitude of the launch vehicle's orbit, it indicates that the undetermined orbit insertion time corresponding to the longitude of the probe's ascending node does not meet the operational requirements. Therefore, the current undetermined orbit insertion time can be excluded and a new undetermined orbit insertion time can be obtained.

[0044] Regarding step S201, determining the undetermined value of the probe's orbit insertion time, if the result of step S203 is negative, the undetermined value of the probe's orbit insertion time needs to be re-determined: As an alternative implementation, after excluding the selected orbital insertion time values ​​on the desired probe launch date, a random time can be set as the current orbital insertion time value from the remaining time.

[0045] As another optional implementation, the current time adjustment value corresponding to the current undetermined value of the ascending node longitude of the current probe's orbit can be determined based on the preset correspondence between the ascending node longitude and the time adjustment value. The current undetermined value of the probe's orbit insertion time can then be adjusted according to the current time adjustment value to obtain the updated undetermined value of the probe's orbit insertion time.

[0046] Optionally, the updated orbital insertion time of the probe is to be determined. satisfy:

[0047] In formula (3), The current orbital insertion time is yet to be determined. Δt Adjusted value for the current time; The longitude of the ascending node of the current probe's orbit is an undetermined value. This represents the maximum longitude of the ascending intersection point of the launch vehicle's orbit. This is the minimum longitude of the ascending intersection point of the launch vehicle's orbit. Let be the angular velocity parameter of Earth's rotation, representing the time elapsed for each degree of Earth's rotation. .

[0048] In this way, when the undetermined longitude of the ascending node of the probe's orbit does not meet the preset range of the longitude of the ascending node of the probe's orbit, the current time adjustment value corresponding to the current undetermined longitude of the ascending node of the probe's orbit can be determined based on the preset correspondence between the longitude of the ascending node and the time adjustment value. The current undetermined orbit insertion time of the probe can then be adjusted according to the current time adjustment value to obtain the updated undetermined orbit insertion time of the probe, thereby improving the efficiency of iteratively obtaining the final orbit insertion time.

[0049] S204. Based on the preset set of launch vehicle entry orbit inclination angles, determine the range of undetermined launch vehicle entry orbit inclination angles to which the undetermined value of the probe entry orbit inclination angle belongs.

[0050] In practical implementation, the set of launch vehicle orbit inclination angles can be obtained by discretizing the entire range of launch vehicle orbit inclination angle values ​​according to actual operational needs. For example, if the entire range of launch vehicle orbit inclination angle values ​​is [20°, 30°], discretizing this range yields the set of launch vehicle orbit inclination angle values ​​as {20°, 24°, 28.7°, 30°}. Then, the range of undetermined launch vehicle orbit inclination angle values ​​containing the current probe orbit inclination angle can be determined from this set. For example, if the set of launch vehicle orbit inclination angle values ​​is {20°, 24°, 28.7°, 30°}, and the undetermined probe orbit inclination angle value is 21°, then the corresponding range of undetermined launch vehicle orbit inclination angle values ​​is [20°, 24°]. That is, the undetermined probe orbit inclination angle value... The undetermined range of values ​​for the orbital inclination angle of the launch vehicle upon entry into orbit satisfies the following relationship:

[0051] in, and All of these are the launch vehicle entry track inclination angles from a preset set of launch vehicle entry track inclination angles.

[0052] S205. Based on the preset correspondence between the launch vehicle's orbital inclination angle and the launch vehicle's taxiing trajectory time, determine the undetermined range of values ​​for the launch vehicle's taxiing trajectory time corresponding to the undetermined range of values ​​for the launch vehicle's orbital inclination angle.

[0053] Since both the launch azimuth and the launch vehicle's taxiing trajectory time affect the longitude of the ascending node and the argument of the perigee of the launch vehicle's orbit, multiple combinations of launch azimuth and taxiing trajectory times can be determined based on the launch vehicle's launch principle. Furthermore, the correspondence between the launch azimuth and the inclination of the launch vehicle's orbit is often fixed; therefore, a preset correspondence between the orbit inclination and the taxiing trajectory time can be constructed based on multiple combinations of these combinations. Correspondingly, based on this preset correspondence, the range of undetermined values ​​for the launch vehicle's taxiing trajectory time corresponding to the undetermined range of values ​​for the orbit inclination can be determined. Furthermore, when the preset correspondence between the probe's orbital inclination and its glide trajectory time does not include the launch vehicle's orbital inclination within the undetermined range of values, the launch vehicle's glide trajectory time corresponding to that orbital inclination can be determined based on rocket launch principles. Understandably, the method for establishing the preset correspondence between the launch vehicle's orbital inclination and its glide trajectory time is existing technology and will not be elaborated upon here.

[0054] S206. Based on the preset correspondence between the perigee argument of the launch vehicle's orbital entry and the launch vehicle's taxiing trajectory time, determine the undetermined range of values ​​for the perigee argument of the launch vehicle's orbital entry corresponding to the undetermined range of values ​​for the launch vehicle's taxiing trajectory time.

[0055] In the specific implementation process, the preset correspondence between the perigee argument of the launch vehicle's orbital insertion and the launch vehicle's coasting trajectory time can be obtained based on the perigee argument trajectory matrix corresponding to the launch vehicle's orbital insertion and coasting trajectory time. The perigee argument trajectory matrix can be constructed based on multiple sets of first launch vehicle orbital parameters. These first launch vehicle orbital parameters include the launch vehicle's orbital inclination, the launch vehicle's coasting trajectory time, and the launch vehicle's orbital perigee argument. The launch vehicle's orbital insertion corresponding to these first launch vehicle orbital parameters is aligned with the lunar probe's Earth-Moon transfer orbit.

[0056] Specifically, the perigee argument trajectory matrix ω satisfies:

[0057] In formula (5), k , j For serial number, The perigee argument trajectory matrix ω is the th k The orbital inclination angle of each launch vehicle upon entry into orbit. The perigee argument trajectory matrix ω is the th j Each launch vehicle's glide trajectory time The perigee argument trajectory matrix ω is the th kThe orbital inclination of the first launch vehicle is related to the first... j The perigee angle of the launch vehicle's orbit corresponding to the launch vehicle's taxiing trajectory time.

[0058] Alternatively, based on the perigee argument trajectory matrix, a grid interpolation method can be used to process each launch vehicle's taxiing trajectory time value within the undetermined range of values ​​for the launch vehicle's taxiing trajectory time, thereby determining the undetermined range of values ​​for the perigee argument of the launch vehicle's orbital insertion trajectory corresponding to the undetermined range of values ​​for the launch vehicle's taxiing trajectory time.

[0059] S207. Determine whether the undetermined value of the perigee angle of the probe's orbital insertion is within the range of the perigee angle values ​​of the launch vehicle's orbital insertion.

[0060] If the result of step S207 is negative, return to step S201; if the result of step S207 is positive, proceed to step S208.

[0061] Regarding step S201, determining the undetermined orbit insertion time of the probe, if the result of step S207 is negative, the process of re-determining the undetermined orbit insertion time of the lunar probe is as follows: As an alternative implementation, after excluding the selected orbital insertion time values ​​on the desired probe launch date, a random time can be set as the current orbital insertion time value from the remaining time.

[0062] As another optional implementation, the current time adjustment value corresponding to the current undetermined value of the ascending node longitude of the probe's orbit can be determined based on the preset correspondence between the ascending node longitude and the time adjustment value. The current undetermined value of the probe's orbit insertion time can then be adjusted according to the current time adjustment value to obtain the updated undetermined value of the probe's orbit insertion time. For details, please refer to the corresponding content of formula (3) above, which will not be repeated here.

[0063] S208. Determine the undetermined value of the launch vehicle's gliding trajectory time based on the undetermined range of the launch vehicle's perigee argument angle, the undetermined range of the launch vehicle's gliding trajectory time, and the undetermined value of the probe's perigee argument angle on its orbital insertion trajectory.

[0064] In the specific implementation process, based on the perigee argument trajectory matrix, the grid interpolation method can be used to determine the undetermined values ​​of the launch vehicle's taxiing trajectory time according to the undetermined range of the launch vehicle's perigee argument, the undetermined range of the launch vehicle's taxiing trajectory time, and the undetermined value of the perigee argument of the probe's entry trajectory. The perigee argument trajectory matrix can be found in formula (5) above, and will not be repeated here.

[0065] Specifically, the launch vehicle's gliding trajectory time is undetermined. It can be determined in the following way:

[0066] In formula (6), The perigee angle of the probe's orbit is an undetermined value. This represents the lower limit of the undetermined range of values ​​for the vehicle's gliding trajectory time. This represents the upper limit of the undetermined range of values ​​for the vehicle's gliding trajectory time. This represents the lower limit of the undetermined range of values ​​for the perigee argument of the launch vehicle. This represents the upper limit of the undetermined range of values ​​for the perigee argument of the launch vehicle. .

[0067] S209. Determine the undetermined value of the longitude of the ascending node of the launch vehicle's entry track based on the undetermined range of the launch vehicle's inclination angle, the undetermined range of the launch vehicle's taxiing trajectory time, and the undetermined value of the launch vehicle's taxiing trajectory time.

[0068] In the specific implementation process, based on the ascending node longitude trajectory matrix, the grid interpolation method can be used to determine the undetermined value of the ascending node longitude of the launch vehicle's entry orbit according to the range of the launch vehicle's orbital inclination angle, the range of the launch vehicle's taxiing trajectory time, and the undetermined value of the launch vehicle's taxiing trajectory time. The ascending node longitude trajectory matrix can be found in formula (2) above, and will not be repeated here.

[0069] S210. Based on the preset correspondence between the longitude of the ascending node and the orbit insertion time, determine the orbit insertion time deviation value according to the undetermined longitude of the ascending node of the probe's orbit and the undetermined longitude of the ascending node of the launch vehicle's orbit. The orbit insertion time deviation value is the difference between the undetermined orbit insertion time of the probe corresponding to the undetermined longitude of the ascending node of the probe's orbit and the undetermined orbit insertion time of the launch vehicle corresponding to the undetermined longitude of the ascending node of the launch vehicle's orbit.

[0070] Optionally, the orbital insertion time deviation value εt It can be determined in the following way:

[0071] In formula (7), Let be the angular velocity parameter of Earth's rotation, representing the time elapsed for each degree of Earth's rotation. ; The longitude of the ascending node of the current probe's orbit is an undetermined value. The longitude of the ascending intersection point of the current launch vehicle orbit is an undetermined value.

[0072] S211. Determine whether the orbital entry time deviation is less than the set deviation threshold.

[0073] If the result of step S211 is negative, return to step S201; if the result of step S211 is positive, execute step S211.

[0074] Regarding step S201, determining the undetermined value of the probe's orbit insertion time, if the result of step S211 is negative, the undetermined value of the probe's orbit insertion time needs to be re-determined: As an alternative implementation, after excluding the selected orbital insertion time values ​​on the desired probe launch date, a random time can be set as the current orbital insertion time value from the remaining time.

[0075] As an optional implementation, the current time adjustment value corresponding to the current undetermined value of the ascending node longitude of the probe's orbit can be determined based on the preset correspondence between the ascending node longitude and the time adjustment value. The current undetermined value of the probe's orbit insertion time can then be adjusted according to the current time adjustment value to obtain the updated undetermined value of the probe's orbit insertion time. For details, please refer to the corresponding content of formula (3) above, which will not be repeated here.

[0076] As an optional implementation, the orbit insertion time deviation value can be used as the current time adjustment value. The current undetermined orbit insertion time value of the detector can then be adjusted based on this current time adjustment value to obtain the updated undetermined orbit insertion time value of the detector. That is, the updated undetermined orbit insertion time value of the detector. satisfy:

[0077] In formula (8), The longitude of the ascending node of the current probe's orbit is an undetermined value. Δt Adjusted value for the current time; εt This represents the current orbital insertion time deviation.

[0078] S212. Determine the undetermined values ​​of the geometric parameters and the undetermined values ​​of the endpoint position parameters of the Earth-Moon transfer orbit based on the undetermined values ​​of the probe's orbit insertion time and orbital parameters.

[0079] In the specific implementation process, since the Earth-Moon transfer orbit takes the shape of a conic section (e.g., a hyperbola) under the gravitational influence of the Earth and the Moon, the geometric parameters of the Earth-Moon transfer orbit and the terminal position parameters of the Earth-Moon transfer orbit can be calculated based on the undetermined values ​​of the probe's entry time and the probe's entry orbit parameters. The embodiments of the present invention will not be elaborated further.

[0080] like Figure 4 As shown: S213. Based on the preset correspondence between the launch vehicle's orbital inclination angle and the launch vehicle's ballistic flight time, determine the undetermined value of the launch vehicle's ballistic flight time according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's gliding ballistic time, and the range of the launch vehicle's gliding ballistic time.

[0081] Alternatively, based on the launch vehicle's ballistic flight time trajectory matrix for launching the lunar probe, a grid interpolation method can be used to determine the undetermined values ​​of the probe's orbital inclination, the undetermined range of the launch vehicle's orbital inclination, the undetermined value of the launch vehicle's coasting trajectory time, and the range of the launch vehicle's coasting trajectory time. The launch vehicle's ballistic flight time trajectory matrix for launching the lunar probe is determined based on multiple sets of third launch vehicle orbital parameters, including the launch vehicle's orbital inclination, the launch vehicle's coasting trajectory time, and the launch vehicle's ballistic flight time. The launch vehicle's orbital trajectory corresponding to these third launch vehicle orbital parameters is aligned with the Earth-Moon transfer orbit corresponding to the lunar probe.

[0082] Specifically, the launch vehicle's ballistic flight time trajectory matrix for launching a lunar probe. satisfy:

[0083] In formula (9), k , j For serial number, For the first k The orbital inclination angle of each launch vehicle upon entry into orbit. For the first j Each launch vehicle's glide trajectory time For the first k The orbital inclination of the first launch vehicle is related to the first... j The launch vehicle's glide trajectory time corresponds to the launch vehicle's trajectory flight time for launching the lunar probe.

[0084] S214. Determine the launch time of the carrier based on the undetermined values ​​of the carrier's ballistic flight time and the probe's orbital insertion time.

[0085] In the specific implementation process, the launch time of the launch vehicle is yet to be determined. satisfy:

[0086] In formula (10), The current orbital insertion time of the probe is yet to be determined. This is the current undetermined value for the launch vehicle's ballistic flight time.

[0087] S215. Based on the preset correspondence between the launch azimuth angle of the launch vehicle, the orbital inclination angle of the launch vehicle, and the time of the launch vehicle's gliding trajectory, the undetermined value of the launch azimuth angle of the launch vehicle is determined according to the undetermined value of the orbital inclination angle of the probe, the undetermined range of the orbital inclination angle of the launch vehicle, the undetermined value of the gliding trajectory time of the launch vehicle, and the range of the gliding trajectory time of the launch vehicle.

[0088] In the specific implementation process, the undetermined launch azimuth angle can be determined using a grid interpolation method based on the launch vehicle's launch azimuth trajectory matrix. This interpolation method considers the undetermined values ​​of the probe's orbital inclination, the undetermined range of the launch vehicle's orbital inclination, the undetermined launch vehicle's coasting trajectory time, and the range of the launch vehicle's coasting trajectory time. The launch vehicle's launch azimuth trajectory matrix is ​​determined based on multiple sets of fourth launch vehicle orbital parameters. These fourth launch vehicle orbital parameters include the launch vehicle's orbital inclination, the launch vehicle's coasting trajectory time, and the launch vehicle's launch azimuth angle. The launch vehicle's orbital trajectory corresponding to these fourth launch vehicle orbital parameters is aligned with the lunar probe's Earth-Moon transfer orbit.

[0089] Specifically, the launch azimuth trajectory matrix of the launch vehicle A satisfy:

[0090] In formula (11), k , j For serial number, For the launch azimuth trajectory matrix of the launch vehicle A The Middle k The orbital inclination angle of each launch vehicle upon entry into orbit. For the launch azimuth trajectory matrix of the launch vehicle A The Middle j Each launch vehicle's glide trajectory time For the launch azimuth trajectory matrix of the launch vehicle A The Middle k The orbital inclination of the first launch vehicle is related to the first... j The launch azimuth angle corresponding to the launch vehicle's glide trajectory time.

[0091] S216. Based on the preset correspondence between the true perimeter angle of the probe's orbital entry, the inclination angle of the launch vehicle's orbital entry, and the time of the launch vehicle's gliding trajectory, the undetermined value of the true perimeter angle of the probe's orbital entry is determined according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time.

[0092] In the specific implementation process, the undetermined value of the true anomaly angle of the probe's orbit can be determined using a grid interpolation method based on the true anomaly angle trajectory matrix of the probe's orbital insertion. This determination is made according to the undetermined values ​​of the probe's orbital inclination, the undetermined range of the launch vehicle's orbital inclination, the undetermined value of the launch vehicle's coasting trajectory time, and the range of the launch vehicle's coasting trajectory time. The true anomaly angle trajectory matrix of the probe's orbital insertion is determined based on multiple sets of fifth launch vehicle orbital parameters. These parameters include the launch vehicle's orbital inclination, the launch vehicle's coasting trajectory time, and the probe's true anomaly angle. The launch vehicle's orbital insertion corresponding to these parameters is aligned with the lunar probe's Earth-Moon transfer orbit.

[0093] Specifically, the ballistic matrix of the probe's true perihelion angle upon entering orbit. f satisfy:

[0094] In formula (11), k , j For serial number, The ballistic matrix for the true perimeter angle of the probe's orbital insertion. f The Middle k The orbital inclination angle of each launch vehicle upon entry into orbit. The ballistic matrix for the true perimeter angle of the probe's orbital insertion. f The Middle j Each launch vehicle's glide trajectory time The ballistic matrix for the true perimeter angle of the probe's orbital insertion. f The Middle k The orbital inclination of the first launch vehicle is related to the first... j The true perimeter angle of the probe's orbit corresponding to the time of the launch vehicle's glide trajectory.

[0095] Understandingly, this application does not limit the order in which the steps of determining the launch time of the launch vehicle (S214), determining the launch azimuth angle of the launch vehicle (S215), and determining the true perigee angle of the probe's orbit (S216) are performed. That is, in this application, steps S214, S215, and S216 can be performed in a specified order. Alternatively, steps S214, S215, and S216 can be performed simultaneously in parallel. The embodiments of this invention are not further limited herein.

[0096] S300. Based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the second lunar orbital inclination, determine the undetermined values ​​of the lunar orbital parameters other than the undetermined value of the first orbital period.

[0097] During the process of a lunar probe leaving its lunar transfer orbit at its perilune and finally landing on the lunar surface, it needs to orbit the moon and perform one or more orbital maneuvers to achieve a successful landing. This process involves at least one lunar orbit primarily utilizing the moon's gravity and another powered descent orbit requiring continuous power output to adjust its attitude and achieve landing. Therefore, based on astrophysics, the undetermined values ​​of the lunar orbit parameters (excluding the undetermined first orbital period) can be determined using the undetermined values ​​of the lunar transfer orbit parameters and the undetermined first orbital period of the first lunar orbit. For example, if a lunar probe's journey from leaving the Earth-Moon transfer orbit to finally landing on the lunar surface involves only one lunar orbit (i.e., the first lunar orbit), then the undetermined values ​​of the lunar orbit parameters for the first lunar orbit, excluding the undetermined value of the first orbit's cycle, can be calculated. Alternatively, if a lunar probe's journey from leaving the Earth-Moon transfer orbit to finally landing on the lunar surface involves multiple lunar orbits (i.e., the first lunar orbit is the first lunar orbit connected to the Earth-Moon transfer orbit), then the undetermined values ​​of the lunar orbit parameters for each lunar orbit (including the first lunar orbit), excluding the undetermined value of the first orbit's cycle, can be calculated.

[0098] This invention provides a specific implementation method to meet the needs of future lunar exploration missions. In this embodiment, during the process of the lunar probe switching from the Earth-Moon transfer orbit to the lunar orbit and finally landing on the lunar surface, the lunar orbit involved in the lunar probe's flight process can be further divided into: a first lunar orbit, a second lunar orbit, a third lunar orbit, and a fourth lunar orbit. The first lunar orbit is theoretically an elliptical orbit; its starting position is the ending position of the Earth-Moon transfer orbit, i.e., the perigee of the Earth-Moon transfer orbit; the ending position of the first lunar orbit is the starting position of the second lunar orbit. The second lunar orbit sequentially includes a theoretically elliptical second orbit change segment and a theoretically circular second circularization segment; the ending position of the second lunar orbit is the starting position of the third lunar orbit. The third lunar orbit sequentially includes a theoretically elliptical third orbit change segment and a theoretically circular third circularization segment; the ending position of the third lunar orbit is the starting position of the fourth lunar orbit. The fourth lunar orbit is theoretically an elliptical orbit. The lunar lander will separate from the lunar orbiter at the beginning of the fourth lunar orbit, while the lunar orbiter will continue to orbit the moon in the third lunar orbit. The end point of the fourth lunar orbit is the beginning point of the powered descent orbit, referred to below as the powered descent initiation point. The powered descent orbit is a closed-loop flight control orbit actively controlled by the lunar lander, and its end point is the landing site of the lunar probe.

[0099] Accordingly, the lunar orbital parameters include: the lunar first orbital parameters corresponding to the lunar first orbit, the lunar second orbital parameters corresponding to the lunar second orbit, the lunar third orbital parameters corresponding to the lunar third orbit, and the lunar fourth orbital parameters corresponding to the lunar fourth orbit.

[0100] For the aforementioned orbits, some lunar orbit parameters (hereinafter referred to as lunar orbit constraint parameters) are pre-set with fixed target values ​​based on the actual needs of the lunar exploration mission. For example, some parameters in the second lunar orbit parameters are pre-selected as lunar orbit constraint parameters and have corresponding target values ​​set according to the needs of the lunar exploration mission; some parameters in the third lunar orbit parameters are pre-selected as lunar orbit constraint parameters and have corresponding target values ​​set according to the needs of the lunar exploration mission; and some parameters in the fourth lunar orbit parameters are pre-selected as lunar orbit constraint parameters and have corresponding target values ​​set according to the needs of the lunar exploration mission. Subsequent calculations derive the remaining undetermined values ​​for the lunar orbit parameters based on these target values ​​for the lunar orbit constraint parameters.

[0101] The parameters of the first lunar orbit include: the shape parameters of the first lunar orbit and the first lunar flight control parameters for the lunar probe when switching from the Earth-Moon transfer orbit to the first lunar orbit. The shape parameters of the first lunar orbit include: the first orbital period, the altitude of the perigee, the altitude of the apogee, and the semi-major axis. The first lunar flight control parameters include: the first adjustment of the orbital maneuver pulse velocity, the perigee velocity, and the first number of lunar orbits corresponding to the first lunar orbit. The first adjustment of the orbital maneuver pulse velocity is the adjustment required for the lunar probe to switch from the perigee position of the Earth-Moon transfer orbit to the first lunar orbit. Since other shape parameters of the first lunar orbit can be deduced from some known shape parameters, the calculation process for some shape parameters will be illustrated later. Shape parameters not mentioned can be deduced from each other and will not be elaborated further. Since other lunar orbit control parameters (such as the first adjustment amount of the orbital maneuver pulse velocity) can be deduced from some of the first lunar orbit control parameters (such as the first lunar orbital perigee velocity), the calculation process of the first adjustment amount of the orbital maneuver pulse velocity will be illustrated in the following text. The first lunar orbit control parameters not mentioned can be deduced from each other, so they will not be elaborated on further.

[0102] The parameters for the second lunar orbit include: the shape parameters of the second orbital maneuver segment, the second lunar flight control parameters for the second orbital maneuver segment, and the shape parameters of the second circular segment. The shape parameters of the second orbital maneuver segment include: the altitude of the perilune, the altitude of the apogee, the semi-major axis of the perilune, and the eccentricity of the perilune. The shape parameters of the second circular segment include: the altitude of the second circular segment and the number of the second lunar orbital ... The second adjustment amount of the orbital maneuver pulse velocity is the adjustment amount required for the lunar probe at the starting position of the second lunar orbit (i.e., the ending position of the first lunar orbit, the perigee of the first lunar orbit) during the transition from the first lunar orbit to the second lunar orbit. The third adjustment amount of the orbital maneuver pulse velocity is the adjustment amount required for the lunar probe at the ending position of the second orbital maneuver segment (i.e., the apogee of the second orbital maneuver segment). Similarly, given some parameters of the second lunar orbit, the remaining parameters can be calculated. Therefore, the calculation process for some parameters of the second lunar orbit will be illustrated below, and the calculation process for parameters not mentioned will not be repeated.

[0103] The parameters for the third lunar orbit include: the shape parameters of the third orbital maneuver segment, the third lunar flight control parameters for the third orbital maneuver segment, and the shape parameters of the third circular segment. The shape parameters of the third orbital maneuver segment include: the altitude of the perigee of the third orbital maneuver segment, the altitude of the apogee of the third orbital maneuver segment, the semi-major axis of the perigee of the third orbital maneuver segment, and the eccentricity of the perigee of the third orbital maneuver segment. The shape parameters of the third circular segment include: the altitude of the third circular segment and the number of the third lunar orbital orbit. The third lunar flight control parameters include: the fourth adjustment amount of the orbital maneuver pulse velocity and the fifth adjustment amount of the orbital maneuver pulse velocity. The constraint parameters for the third lunar orbit corresponding to the third lunar orbit include the semi-major axis of the perigee of the third orbital maneuver segment, the semi-major axis of the apogee of the third orbital maneuver segment, the altitude of the third circular segment, and the number of the third lunar orbital orbit. The fourth adjustment of the orbital maneuver pulse velocity is the adjustment required at the starting position of the third lunar orbit (i.e., the ending position of the second lunar orbit, the perigee of the second lunar orbit) during the transition from the second lunar orbit to the third lunar orbit. The fifth adjustment of the orbital maneuver pulse velocity is the adjustment required at the ending position of the third orbital maneuver segment (i.e., the apogee of the third orbital maneuver segment). Similarly, given some parameters of the third lunar orbit, the remaining parameters can be calculated. Therefore, the calculation process for some parameters of the third lunar orbit will be illustrated below, and the calculation process for parameters not mentioned will not be repeated.

[0104] The parameters of the fourth lunar orbit include: the latitude argument of the initial position of the fourth lunar orbit, the sixth adjustment of the orbital maneuver pulse velocity, the latitude argument of the starting point of the powered descent, and the semi-major axis of the fourth lunar orbit. Among these, the constraint parameters of the fourth lunar orbit include its semi-major axis. The sixth adjustment of the orbital maneuver pulse velocity is the adjustment required for the lunar lander to switch from the third lunar orbit to the fourth lunar orbit at the initial position of the fourth lunar orbit (i.e., the end position of the third lunar orbit). Similarly, given some of the fourth lunar orbit parameters, the remaining parameters can be calculated. Therefore, the calculation process for some fourth lunar orbit parameters will be illustrated below, while the calculation process for parameters not mentioned will not be elaborated upon.

[0105] The parameters for powered descent trajectory include parameters such as powered descent range.

[0106] The calculation process for the undetermined values ​​of the lunar orbital parameters is explained in detail below. For ease of reading and understanding, unless otherwise specified, the symbols in the formulas involved in the calculation of the undetermined lunar orbital parameters are indicated by the subscript "". e "Indicates the first lunar orbit, symbolized by a subscript " c "1" indicates the second lunar orbit, with the symbol subscript " c "2" indicates the third lunar orbit, with the symbol subscript " d "Indicates the fourth lunar orbit, symbolized by the subscript " p "Indicates the lunar perigee, indicated by the subscript " a The symbol "" indicates the apogee of the lunar orbit. A superscript "-" indicates the parameters of the lunar probe at that position without maneuvering, and a superscript "+" indicates the parameters after the lunar probe has maneuvered at that position. a "Indicates orbital eccentricity, symbol " r "Indicates the distance from the center of the moon, symbol " h "Indicates orbital altitude, symbol " v "Indicates the flight speed of the lunar probe, symbol " n "" indicates the average angular velocity of the lunar probe's orbit.

[0107] like Figure 5 As shown, the calculation process for the undetermined values ​​of the lunar orbital parameters specifically includes the following: S301. Based on the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined value of the first orbital period of the first lunar orbit, determine the undetermined values ​​of the shape parameters of the first lunar orbit, excluding the undetermined value of the first orbital period.

[0108] In the specific implementation process, the semi-major axis value of the first lunar orbit is yet to be determined. satisfy:

[0109] In formula (12), The semi-major axis of the first lunar orbit is a value yet to be determined; The distance from the lunar center to the perigee of the first lunar orbit is an undetermined value, which is the distance from the lunar center to the perigee of the Earth-Moon transfer orbit. This value was obtained during the calculation of the aforementioned Earth-Moon transfer orbit parameters. This represents the distance from the lunar center to the apogee of the first lunar orbit.

[0110] First orbital period expected value satisfy:

[0111] In formula (13), The expected value for the first orbital cycle; The semi-major axis of the first lunar orbit is a value yet to be determined; μ is the lunar gravitational constant.

[0112] Therefore, based on the above formulas (12) and (13), when the expected value of the first orbital period has never been determined, we can... The target value for the distance between the apogee and the lunar center of the first lunar orbit is set. Then, combined with the undetermined values ​​of the Earth-Moon transfer orbit (such as the undetermined value for the distance between the perigee and the lunar center of the Earth-Moon transfer orbit), the undetermined value for the orbital period is calculated. This leads to the determination of the undetermined values ​​for other shape parameters of the first lunar orbit besides the undetermined orbital period (such as the undetermined value for the semi-major axis of the first lunar orbit). Subsequently, when the existing first orbital period determinants need to be updated, the updated first orbital period determinants, combined with the undetermined values ​​of the Earth-Moon transfer orbit (e.g., the undetermined value of the distance between the Earth and the Moon's center and the perigee of the Earth-Moon transfer orbit), can be used to calculate the undetermined values ​​of the first lunar orbit shape parameters (e.g., the undetermined value of the semi-major axis of the first lunar orbit). The distance between the apogee and the lunar center of the first lunar orbit is yet to be determined. wait).

[0113] S302. Determine the undetermined values ​​of the first lunar orbital shape parameters based on the undetermined values ​​of the first lunar orbital shape parameters.

[0114] In practical implementation, the undetermined value of the perilune velocity of the first lunar orbit can be determined based on the undetermined values ​​of the shape parameters of the first lunar orbit. For example, the undetermined value of the perilune velocity of the first lunar orbit can be determined using the following formula. :

[0115] In formula (14), The velocity at the perigee of the first lunar orbit is an undetermined value; The expected value for the first orbital cycle; The semi-major axis of the first lunar orbit is a value yet to be determined; μ is the lunar gravitational constant.

[0116] Subsequently, based on the undetermined values ​​of the perilune velocity of the first lunar orbit and the perilune velocity of the Earth-Moon transfer orbit, the undetermined value of the first adjustment amount for the orbital maneuver pulse velocity was determined. This first adjustment amount for the orbital maneuver pulse velocity is the amount of orbital maneuver pulse velocity adjustment required when the lunar probe switches from the perilune position of the Earth-Moon transfer orbit to the first lunar orbit. For example, the undetermined value of the first adjustment amount for the orbital maneuver pulse velocity is determined using the following formula. :

[0117] In formula (15), The first adjustment value for the track maneuver pulse velocity is to be determined. The velocity at the perigee of the first lunar orbit is an undetermined value; The velocity of the lunar probe at the perigee of the first lunar orbit when it is not maneuvering is the undetermined value, that is, the undetermined flight velocity at the perigee of the Earth-Moon transfer orbit, which is obtained in the aforementioned calculation process of the Earth-Moon transfer orbit parameters.

[0118] Next, the lunar sub-satellite trajectory is determined based on the undetermined values ​​of the first lunar orbit shape parameters. Then, based on this trajectory and the target latitude value of the lunar landing site, the undetermined longitude value of the lunar reference point is determined. The longitude and latitude of the lunar sub-satellite trajectory have a functional relationship. Therefore, based on this relationship, the undetermined longitude value of the lunar reference point is determined when the latitude of the lunar sub-satellite trajectory is equal to the target latitude value of the lunar landing site.

[0119] Subsequently, the first longitude control deviation value is determined based on the target longitude value of the lunar landing point and the undetermined longitude value of the lunar reference point. Then, the undetermined value of the first lunar orbit number is determined based on the first longitude control deviation value and the first orbital period undetermined value.

[0120] In the specific implementation process, the target longitude value of the lunar landing site location... Longitude relative to the lunar reference point is undetermined. The difference is the first longitude control deviation value. satisfy:

[0121] The number of orbits in the first lunar flight is yet to be determined. satisfy:

[0122] In formula (17), The number of orbits in the first lunar orbit is yet to be determined. This is the current first longitude control deviation value. The expected value for the current first orbital cycle is set. This is the angular velocity of the moon's rotation.

[0123] S303. Determine the undetermined values ​​of the shape parameters of the second orbital segment based on the undetermined values ​​of the first lunar orbital parameters and the target values ​​of the second lunar orbital constraint parameters, and determine the undetermined values ​​of the second lunar orbital flight control parameters and the undetermined values ​​of the shape parameters of the second orbital segment based on the undetermined values ​​of the shape parameters of the second orbital segment.

[0124] In the specific implementation process, the undetermined values ​​of the shape parameters of the second orbital change segment can first be determined based on the undetermined values ​​of the perilune altitude of the first lunar orbit and the target values ​​of the second circular segment altitude. For example, the undetermined value of the semi-major axis of the perilune of the second orbital change segment can be determined using the following formula. :

[0125] In formula (18), The semi-major axis value at the near-lunar point of the second orbital change segment is yet to be determined; The target height for the second circular segment; The number of the first orbits of the lunar probe around the moon is yet to be determined. The lunar perigee altitude of the first orbit after the lunar orbit is yet to be determined. This is the average radius of the moon.

[0126] The undetermined value of the near-lunar eccentricity in the second orbital change segment is determined using the following formula. :

[0127] In formula (19), The eccentricity of the near-lunar point in the second orbital change segment is an undetermined value. The semi-major axis value at the near-lunar point of the second orbital change segment is yet to be determined; The target height for the second circular segment; The number of orbits the lunar probe made during its first lunar orbit is yet to be determined. The altitude of the perigee of the first lunar orbit after the lunar orbit is yet to be determined.

[0128] Then, the undetermined value of the second adjustment amount of the track maneuver pulse velocity is determined by the following formula. :

[0129] In formula (20), The second adjustment value for the track maneuver pulse velocity is to be determined. The average angular velocity of the lunar probe at the perigee position during the second orbital maneuver is an undetermined value. The number of the first orbits of the lunar probe around the moon is yet to be determined. The eccentricity of the first lunar orbit near the lunar periphery is yet to be determined. The adjustment amount of the semi-major axis near the lunar orbit point in the second orbit change phase is to be determined. The semi-major axis of the lunar probe is to be determined when it is at the perigee position during the second orbital maneuver and has not made any maneuvers. μ The gravitational constant of the moon; The number of the first orbits of the lunar probe around the moon is yet to be determined. The altitude of the apogee of the first lunar orbit after the lunar orbit is yet to be determined. The number of the first orbits of the lunar probe around the moon is yet to be determined. The lunar perigee altitude of the first orbit after the lunar orbit is yet to be determined. The semi-major axis value at the near-lunar point of the second orbital change segment is yet to be determined; This is the target height value for the second circular segment.

[0130] The undetermined value of the third adjustment amount for the track maneuvering pulse velocity is determined using the following formula. :

[0131] In formula (21), The third adjustment value for the track maneuver pulse velocity is to be determined. The average angular velocity of the lunar probe at the apogee position during the second orbital maneuver is an undetermined value. The eccentricity of the near-lunar point in the second orbital change segment is an undetermined value. The semi-major axis adjustment amount at the far-lunar point of the second orbit change segment is to be determined. The semi-major axis of the lunar probe after maneuvering at the perilune position during the second orbital maneuver phase is a value to be determined. μ The gravitational constant of the moon; The target height for the second circular segment; The number of orbits the lunar probe made during its first lunar orbit is yet to be determined. The lunar perigee altitude of the first orbit after the lunar orbit is yet to be determined. This is the target value for the semi-major axis at the far point of the second orbital change segment.

[0132] Furthermore, based on the undetermined values ​​of the shape parameters of the second orbital change segment calculated in the above process, the undetermined values ​​of the second lunar orbital flight control parameters, and the laws of orbital mechanics, the undetermined values ​​of the shape parameters of the second circular segment (e.g., the undetermined value of the altitude of the second circular segment) can be deduced. Further explanation is omitted due to space limitations.

[0133] S304. Based on the undetermined values ​​of the second lunar orbit parameters and the target values ​​of the third lunar orbit constraint parameters, determine the undetermined values ​​of the shape parameters of the third orbit change segment, and based on the undetermined values ​​of the shape parameters of the third orbit change segment, determine the undetermined values ​​of the third lunar flight control parameters and the undetermined values ​​of the shape parameters of the third circular segment.

[0134] In the specific implementation process, the undetermined values ​​of the shape parameters of the third orbital change segment can first be determined based on the undetermined values ​​of the perilune altitude of the second lunar orbit and the target value of the third circular segment altitude. For example, the undetermined value of the semi-major axis of the perilune of the third orbital change segment can be determined using the following formula. :

[0135] In formula (22), This is the target value for the semi-major axis at the near-lunar point of the third orbital change segment; The target height for the third circular segment; The number of the second lunar orbits of the lunar probe is yet to be determined. The lunar perigee altitude of the second lunar orbit after the lunar orbit is yet to be determined. This is the average radius of the moon.

[0136] The undetermined value of the near-lunar eccentricity in the third orbital change segment is determined using the following formula. :

[0137] In formula (23), The eccentricity of the near-lunar point in the third orbital change segment is an undetermined value. This is the target value for the semi-major axis at the near-lunar point of the third orbital change segment; The target height for the third circular segment; The number of the second lunar orbits of the lunar probe is yet to be determined. The altitude of the perigee of the second lunar orbit after the lunar orbit is yet to be determined.

[0138] Subsequently, the undetermined values ​​of the third lunar orbit control parameters were determined based on the undetermined values ​​of the shape parameters of the third orbital change segment.

[0139] For example, the undetermined value of the fourth adjustment amount of the track maneuvering pulse velocity is determined by the following formula. :

[0140] In formula (24), The fourth adjustment value for the track maneuver pulse velocity is to be determined. The average angular velocity of the lunar probe at the perigee position during the third orbital maneuver is an undetermined value. The number of the second lunar orbits of the lunar probe is yet to be determined. The eccentricity of the second lunar orbit after the moon's orbit is yet to be determined. The adjustment amount of the semi-major axis near the lunar orbit point in the third orbit change phase is to be determined. The number of the second lunar orbits of the lunar probe is yet to be determined. The semi-major axis of the second lunar orbit after the moon's orbit is yet to be determined. μ The gravitational constant of the moon; The number of the second lunar orbits of the lunar probe is yet to be determined. The apogee altitude of the second lunar orbit after the lunar orbit is yet to be determined. The target height for the third circular segment; This is the target value for the semi-major axis at the far point of the third orbital change segment.

[0141] For example, the fifth adjustment value of the track maneuver pulse velocity is determined by the following formula. :

[0142] In formula (25), The fifth adjustment value for the track maneuver pulse velocity is to be determined. The average angular velocity of the lunar probe at the apogee position during the third orbital maneuver is an undetermined value. The eccentricity of the perigee of the third lunar orbit is an undetermined value. The adjustment amount of the semi-major axis at the far-lunar point of the third orbit change segment is to be determined. The semi-major axis of the lunar probe after maneuvering at the perilune position during the third orbital maneuver phase is a value to be determined. μ The gravitational constant of the moon; The number of the second lunar orbits of the lunar probe is yet to be determined. The height of the second rounded segment is yet to be determined. The target height for the third circular segment; This is the target value for the semi-major axis at the far point of the third orbital change segment.

[0143] Furthermore, based on the undetermined values ​​of the shape parameters of the third orbital change segment calculated in the above process, the undetermined values ​​of the third lunar orbital flight control parameters, and the laws of orbital mechanics, the undetermined values ​​of the shape parameters of the third circular segment (e.g., the undetermined value of the altitude of the third circular segment) can be deduced. Further explanation is omitted due to space limitations.

[0144] S305. Determine the undetermined values ​​of the fourth lunar orbit parameters based on the second undetermined value of the lunar orbit inclination angle, the target value of the lunar landing point position, the target value of the powered descent orbit parameters, the target value of the fourth lunar orbit constraint parameters, and the undetermined values ​​of the third lunar orbit parameters.

[0145] In the specific implementation process, the undetermined value of the latitude argument of the lunar landing point can be determined first based on the target latitude value of the lunar landing point location and the second undetermined value of the lunar orbit inclination. u’ :

[0146] In formula (26), u’ The latitude argument of the lunar landing site is an undetermined value; The second undetermined value for the lunar orbital inclination. ; The target latitude value for the lunar landing site.

[0147] Then, based on the undetermined value of the latitude argument of the lunar landing site location. u’ The latitude angle of depression at the starting point of the dynamic descent is to be determined. :

[0148] In formula (27), The latitude angle of depression at the starting point of the powered descent is an undetermined value. u’ The latitude argument of the lunar landing site is an undetermined value. D This represents the target range for powered descent on a powered descent trajectory. This is the average radius of the moon.

[0149] Then, based on the undetermined value of the latitude argument of the starting point of the dynamic descent... The latitudinal argument of the fourth lunar orbit starting position is yet to be determined. :

[0150] In formula (28), The latitude argument of the descending orbit control point is an undetermined value. The latitude angle of depression at the point of descent on the powered descent trajectory is undetermined.

[0151] The change in the semi-major axis after the fourth lunar orbit control is an undetermined value. for:

[0152] In formula (29), The value to be determined is the change in the semi-major axis after the control of the fourth lunar orbit. The target value for the semi-major axis of the fourth lunar orbit can be set to 15km during implementation; The height of the third circular segment is an undetermined value.

[0153] The sixth adjustment value of the track maneuver pulse velocity is to be determined. for:

[0154] In formula (30), The sixth adjustment value for the track maneuver pulse velocity is to be determined. The value to be determined is the change in the semi-major axis after the control of the fourth lunar orbit. The value for the average angular velocity of the lunar probe when it is in its initial position in the fourth lunar orbit and has not made any maneuvers is to be determined.

[0155] S400. Determine the undetermined value of the lunar landing point location based on the undetermined values ​​of the lunar orbit parameters.

[0156] In the specific implementation process, the final lunar landing point location of the lunar probe can be calculated based on the aforementioned lunar orbit parameters combined with the powered descent orbit parameters. Due to space limitations, this will not be elaborated further.

[0157] S500: Determine whether the landing point deviation requirement is met based on the undetermined value of the lunar landing point position and the target value of the lunar landing point position.

[0158] In the specific implementation process, the landing point deviation requirement is that the difference between the undetermined value of the lunar landing point position and the target value of the lunar landing point position is less than the preset lunar landing point position deviation threshold.

[0159] If the result of step S500 is negative, proceed to step S600; if the result of step S500 is positive, proceed to step S700.

[0160] S600, Adjust the first orbital period setpoint. Return to step S300.

[0161] As an optional implementation, during the readjustment of the expected first orbital period value, the current expected first orbital period value can be increased or decreased by a preset orbital period adjustment amount based on the direction of deviation between the expected lunar landing point position and the target lunar landing point position. That is, when the direction of deviation between the expected lunar landing point position and the target lunar landing point position is opposite, the direction of adjustment for the expected first orbital period value is also opposite.

[0162] As another alternative implementation, during the process of readjusting the expected value of the first orbital period, the expected value of the lunar landing point position can be calculated based on the expected values ​​of the lunar orbit parameters, the orbital period adjustment amount can be determined based on the current expected value of the lunar landing point position and the target value of the lunar landing point position, and the adjusted expected value of the first orbital period can be determined based on the current expected value of the first orbital period and the orbital period adjustment amount.

[0163] Optionally, based on the previously calculated values ​​of the lunar orbital parameters, the final lunar landing site location of the lunar probe following these orbits can be determined. Furthermore, based on the currently undetermined longitude of the lunar landing site location... and the target longitude value of the lunar landing site Determine the orbital period adjustment amount. Orbital period adjustment amount satisfy:

[0164] In formula (31), This is the amount of adjustment for the orbital period; The longitude of the lunar landing site is an undetermined value. This represents the target longitude value for the lunar landing site. The number of orbits in the first lunar orbit is yet to be determined. This is the angular velocity of the moon's rotation.

[0165] S700: Determine the undetermined value of the lunar surface working time based on the undetermined values ​​of the lunar orbit parameters.

[0166] In the specific implementation process, once the undetermined values ​​of the lunar orbit parameters are determined, the time intervals during which the lunar probe's orbiter orbits the moon in the determined lunar orbit while waiting for the lunar lander to land and return can be calculated. This time interval represents the undetermined value of the lunar lander's lunar surface working time. The specific calculation process can be implemented according to the actual situation of the lunar orbit. For example, if the lunar orbit consisting of the first to fourth lunar orbits, as exemplified in this paper, is used, the lunar probe's orbiter will orbit the moon in the third lunar orbit while waiting for its mission. Therefore, the time intervals during which the lunar probe's orbiter passes the lunar landing point multiple times (e.g., twice) can be calculated based on the undetermined values ​​of the third lunar orbit parameters. This time interval is the current undetermined value of the lunar surface working time.

[0167] S800: Determine whether the lunar surface working time deviation requirement is met based on the undetermined value of the lunar surface working time and the target value of the lunar surface working time.

[0168] In the specific implementation process, the deviation requirement for lunar working time is that the deviation between the undetermined value of lunar working time and the target value of lunar working time is less than the preset deviation threshold for lunar working time.

[0169] If the result of step S800 is negative, proceed to step S900; if the result of step S800 is negative, proceed to step S1000.

[0170] S900, Adjust the second undetermined value of the lunar orbit inclination angle. Return to step S200.

[0171] As an alternative implementation, after excluding the previously selected second undetermined values ​​for the lunar orbit inclination, a value can be randomly set within the range of lunar orbit inclination values ​​as the current second undetermined value for the lunar orbit inclination.

[0172] As an alternative implementation, during the process of readjusting the second undetermined value of the lunar orbit inclination, the adjusted second undetermined value of the lunar orbit inclination can be obtained by increasing or decreasing the current second undetermined value of the lunar orbit inclination by a preset first adjustment amount, based on the relationship between the undetermined value of the lunar surface working time and the target value of the lunar surface working time. That is, the direction of adjustment for the second undetermined value of the lunar orbit inclination when the undetermined value of the lunar surface working time is less than the target value of the lunar surface working time is opposite to the direction of adjustment when the undetermined value of the lunar surface working time is greater than the target value of the lunar surface working time.

[0173] S1000. Determine whether the lunar orbit inclination convergence requirement is met based on the difference between the current first undetermined value and the current second undetermined value.

[0174] In the specific implementation process, the convergence requirement for the lunar orbit inclination angle can include the difference between the current undetermined first value and the current undetermined second value of the lunar orbit inclination angle being less than a preset convergence threshold. The preset convergence threshold can be set to a value close to 0. That is, when the first undetermined value and the second undetermined value of the lunar orbit inclination angle are approximately equal, the lunar probe can successfully assemble its various orbits from Earth to the Moon, achieving the design goal.

[0175] If the result of step S1000 is negative, then step S1100 is executed; if the result of step S1000 is positive, then step S1200 is executed.

[0176] S1100, Adjust the lunar orbital inclination angle to the first undetermined value. Return to step S200.

[0177] As an optional implementation, if the current lunar orbit inclination convergence requirement is not met, then during the process of readjusting the first undetermined value of the lunar orbit inclination, the current first undetermined value of the lunar orbit inclination can be increased or decreased by a preset second adjustment amount based on the relationship between the undetermined value of the lunar surface working time and the target value of the lunar surface working time. That is, the direction of adjustment for the first undetermined value of the lunar orbit inclination when the undetermined value of the lunar surface working time is less than the target value of the lunar surface working time is opposite to the direction of adjustment when the undetermined value of the lunar surface working time is greater than the target value of the lunar surface working time. Furthermore, in this embodiment, if the preset value of the second adjustment amount for the lunar orbit inclination is very small, then the convergence requirement for the lunar orbit inclination can also include the first difference between the current first undetermined value and the current second undetermined value of the lunar orbit inclination, and the second difference between the first undetermined value and the second undetermined value of the lunar orbit inclination determined during the previous execution of step S1000; the two values ​​are opposite in sign. That is, the first undetermined value of the lunar orbit inclination corresponding to the previous execution of step S1000 and the first undetermined value of the lunar orbit inclination corresponding to the current execution of step S1000 are close to the ideal optimal value.

[0178] As another optional implementation, if the current lunar orbit inclination convergence requirement is not met, then during the process of readjusting the first undetermined value of the lunar orbit inclination, the current third adjustment amount of the lunar orbit inclination corresponding to the current lunar surface working time deviation value can be determined according to the preset correspondence between the lunar surface working time deviation value and the third adjustment amount of the lunar orbit inclination. The adjusted first undetermined value of the lunar orbit inclination is then determined according to the current first undetermined value of the lunar orbit inclination and the current third adjustment amount of the lunar orbit inclination.

[0179] It is understood that other methods can also be used to adjust the first undetermined value of the lunar orbit inclination, and this invention does not impose too many limitations.

[0180] S1200, Determine the current undetermined values ​​of all parameters except for the lunar surface working time as the corresponding parameter target values.

[0181] It is understandable that, since the first undetermined value and the second undetermined value of the lunar orbit inclination are already approximately equal at this point, there is little difference in choosing either the first undetermined value or the second undetermined value of the lunar orbit inclination as the target value of the lunar orbit inclination.

[0182] The simulation results of the method for determining the flight trajectory parameters of a lunar probe provided in this embodiment of the invention are given below: (1) Simulation parameter setting The launch date of the lunar probe is set for October 12, 2028. The target landing site location on the lunar surface is: longitude -7°, latitude -4°. The target duration of operation on the lunar surface is 3 days.

[0183] The relationship between the orbital parameters of the launch vehicle is shown in the table below: Table 1. Correspondence between orbital parameters for launch vehicle entry

[0184] The lunar probe's initial orbital inclination from Earth was 24.9°, its perigee altitude in the Earth-Moon transfer orbit was 270km, its flight time in the Earth-Moon transfer orbit was 112 hours, and it reached a retrograde orbit in the lunar orbit. Its initial lunar-solid system orbital inclination was 176°, and its perigee altitude in the Earth-Moon transfer orbit was 200km.

[0185] The dynamics model of the Earth-Moon transfer orbit takes into account factors such as the Earth's central gravity, the Earth's non-spherical 8x8 shape, and gravitational perturbations from the Sun, Moon, and other three bodies.

[0186] The lunar orbit dynamics model takes into account factors such as the lunar central gravity, the non-spherical shape of the Moon (21x21), and gravitational perturbations from the Sun-Earth tri-body system.

[0187] The lunar orbit flight sequence is shown in Table 2: Table 2 Lunar Orbit Flight Timing

[0188] 2) Design Objectives

[0189] The core orbital parameters of the design include: lunar probe launch time, launch vehicle glide trajectory time, probe orbit insertion time, Earth-Moon transfer orbit parameters, lunar orbit parameters, lunar landing time, and lunar surface working duration.

[0190] 3) Three-layer computational process of integrated joint design

[0191] Following a three-layer iterative calculation process based on the integrated design of all orbital parameters, the inner layer calculates the lunar landing trajectory deviation based on the lunar orbit flight sequence, iteratively determines the first lunar orbit period, and continues until the landing trajectory deviation is less than 0.01 degrees, typically involving about 6 iterations. The second layer calculates the lunar surface working time based on the lunar orbit, and adjusts the lunar orbit inclination angle based on the deviation in lunar surface working time, until the difference between the lunar surface working time and the target requirement of 3 days is less than 0.2 days, typically involving about 8 iterations. The outer layer uses the lunar orbit inclination angle as the target inclination angle to calculate the Earth-Moon transfer orbit, iteratively calculates the Earth-Moon transfer orbit parameters, and continues until the difference between two consecutive lunar orbit inclination angles is less than 0.01 degrees, typically involving about 4 iterations.

[0192] 4) Design Track Results

[0193] The design results of the launch trajectory parameters are shown in Table 3: Table 3 Launch Trajectory Parameters

[0194] The design results of the Earth-Moon transfer orbit parameters and the lunar orbit parameters are shown in Table 4: Table 4. Parameters of Earth-Moon Transfer Orbit and Lunar Orbit:

[0195] The results of lunar landing time, lunar surface working duration, and lunar takeoff time on the co-orbital plane are shown in Table 5: Table 5 Results of lunar landing time, lunar surface working duration, and lunar takeoff time

[0196] According to the orbital design results, the flight time in the first lunar orbit is 11.8 days, and the apogee altitude of the first lunar orbit is 6913.895 km; the total velocity increment for the probe to achieve lunar landing is 866.301 m / s; the lunar probe will accurately land at the predetermined lunar landing site, and the lunar surface working time between lunar launch and landing on the shared orbital plane will be 3.080 days. The orbital design results meet the design objectives.

[0197] Based on the same inventive concept, embodiments of the present invention also provide a device for determining the flight trajectory parameters of a lunar probe, such as... Figure 6 As shown, it includes: The inner iteration module M1 is used to determine the undetermined values ​​of lunar orbit parameters other than the undetermined value of the first orbital period, based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the second lunar orbital inclination; wherein, the first lunar orbit is the orbit in the lunar orbit that connects with the Earth-Moon transfer orbit; determine the undetermined value of the lunar landing point position based on the undetermined values ​​of the lunar orbit parameters, and determine whether the landing point deviation requirement is met based on the undetermined value of the lunar landing point position and the target value of the lunar landing point position; if the landing point deviation requirement is not met, adjust the undetermined value of the first orbital period, and return to the step of determining the undetermined values ​​of lunar orbit parameters other than the undetermined value of the first orbital period, based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the second lunar orbital inclination; The intermediate iteration module M2 is used to determine the undetermined value of the lunar surface working time based on the undetermined value of the lunar orbit parameters if the landing point deviation requirement is met; and to determine whether the lunar surface working time deviation requirement is met based on the undetermined value of the lunar surface working time and the target value of the lunar surface working time. If the lunar surface working time deviation requirement is not met, the second undetermined value of the lunar orbit inclination is adjusted, and the process returns to the step of determining the undetermined values ​​of the lunar orbit parameters other than the first undetermined value of the first orbital circumference based on the undetermined value of the Earth-Moon transfer orbit parameters, the first undetermined value of the lunar orbital circumference, and the second undetermined value of the lunar orbit inclination. The outer iteration module M3 is used to determine the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination angle, and set the first undetermined value of the lunar orbit inclination angle as the second undetermined value of the lunar orbit inclination angle; and, if the lunar surface working time deviation requirement is met, then it is determined whether the lunar orbit inclination angle convergence requirement is met based on the difference between the current first undetermined value of the lunar orbit inclination angle and the current second undetermined value of the lunar orbit inclination angle; if the lunar orbit inclination angle convergence requirement is not met, then the first undetermined value of the lunar orbit inclination angle is adjusted, and the process returns to the step of determining the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination angle. The result output module M4 is used to determine the current undetermined values ​​of each parameter, except for the lunar surface working time, as the corresponding parameter target values ​​if the lunar orbit inclination angle convergence requirement is met.

[0198] It should be understood that the device embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces, indirect couplings, or communication connections between devices or modules, and may be electrical, mechanical, or other forms. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, the functional modules in the various embodiments of this application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0199] Since the specific operation methods of each module of the lunar probe flight trajectory parameter determination device have been described in detail in the corresponding lunar probe flight trajectory parameter determination methods, they will not be repeated here. For details, please refer to the previous implementation.

[0200] Based on the same inventive concept, embodiments of this application also provide an electronic device, such as... Figure 7 As shown, it includes: a processor 110 and a memory 120 for storing executable instructions of the processor 110; wherein the processor 110 is configured to execute the instructions to implement the method for determining the flight trajectory parameters of the lunar probe.

[0201] In specific implementations, the device may vary significantly due to differences in configuration or performance. It may include one or more processors 110, memory 120, and computer-readable storage media 130. The memory 120 and / or computer-readable storage media 130 may contain one or more application programs 131 or data 132. The memory 120 and / or computer-readable storage media 130 may also contain one or more operating systems 133, such as Windows, Mac OS, Linux, iOS, Android, Unix, FreeBSD, etc. The memory 120 and computer-readable storage media 130 may be temporary or persistent storage. The application program 131 may include one or more of the aforementioned modules (…). Figure 7 (Not shown in the diagram), each module may include a series of instruction operations. Furthermore, the processor 110 may be configured to communicate with the computer-readable storage medium 130 and execute a series of instruction operations in the computer-readable storage medium 130 on the device. The device may also include one or more power supplies (…). Figure 7 (not shown in the image); one or more network interfaces 140, the network interface 140 including a wired network interface 141 and / or a wireless network interface 142; one or more input / output interfaces 143.

[0202] Based on the same inventive concept, embodiments of this application provide a computer-readable storage medium storing computer program code, which, when executed on a computer, enables the computer to implement the method for determining the flight trajectory parameters of the lunar probe.

[0203] The computer-readable storage medium can be any available medium that a computer can store, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disks, hard disks, USB flash drives, magnetic tapes, read-only memory (ROM), random access memory (RAM)), optical media (e.g., high-density digital video discs (DVDs), video compact discs (VCDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0204] Since the principle of the computer-readable storage medium used to solve the problem is the same as the method for determining the flight trajectory parameters of the lunar probe described above, the implementation of the computer-readable storage medium can be found in the implementation of the method, and the repetition will not be repeated.

[0205] Based on the same inventive concept, this application also provides a computer program product, which includes computer program code. When the computer program code is run on a computer, it enables the computer to implement the method for determining the flight trajectory parameters of the lunar probe.

[0206] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0207] Since the principle by which the above-mentioned computer program product solves the problem is the same as the method for determining the flight trajectory parameters of the lunar probe described above, the implementation of the above-mentioned computer program product can refer to the implementation of the method, and the repeated parts will not be described again.

[0208] In summary, the method for determining the flight trajectory parameters of a lunar probe provided by this invention addresses the parameter design requirements of various segments of the lunar probe's flight trajectory from Earth to the Moon. It proposes an integrated joint design method for trajectory parameters, with the overall design process comprising a three-layer iterative calculation flow: the inner layer iterates the corresponding parameters of the lunar orbit to achieve a precise landing point on the lunar surface; the second layer iterates the lunar orbit inclination angle to ensure precise lunar surface working time; and the outer layer iterates the launch trajectory, Earth-Moon transfer orbit, and lunar orbit parameters. Ultimately, this achieves seamless connection between the various flight trajectories of the lunar probe from Earth to lunar landing.

[0209] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0210] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0211] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0212] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1The steps of the function specified in one or more boxes.

[0213] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for determining the flight trajectory parameters of a lunar probe, characterized in that, The method includes: The undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters are determined based on the first undetermined value of the lunar orbit inclination angle, and the first undetermined value of the lunar orbit inclination angle is set as the second undetermined value of the lunar orbit inclination angle; Based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the lunar orbit inclination angle, the undetermined values ​​of the lunar orbit parameters, excluding the undetermined value of the first orbital period, are determined; wherein, the first lunar orbit is the orbit in the lunar orbit that connects with the Earth-Moon transfer orbit; The undetermined value of the lunar landing point position is determined based on the undetermined value of the lunar orbit parameters, and the landing point deviation requirement is judged based on the undetermined value of the lunar landing point position and the target value of the lunar landing point position. If the landing point deviation requirement is not met, the first orbital period expectation value is adjusted, and the process returns to the step of determining the lunar orbital parameter expectation values ​​other than the first orbital period expectation value based on the lunar transfer orbit parameter expectation values, the first lunar orbital period expectation value, and the second lunar orbital inclination expectation value; if the landing point deviation requirement is met, the lunar surface working time expectation value is determined based on the lunar orbital parameter expectation values, and the lunar surface working time expectation value and the lunar surface working time target value are used to determine whether the lunar surface working time deviation requirement is met; If the lunar surface working time deviation requirement is not met, the second undetermined value of the lunar orbit inclination is adjusted, and the process returns to the step of determining the undetermined values ​​of the lunar orbit parameters other than the first undetermined value of the orbital period based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the first undetermined value of the orbital period of the first lunar orbit, and the second undetermined value of the lunar orbit inclination; if the lunar surface working time deviation requirement is met, the difference between the current first undetermined value of the lunar orbit inclination and the current second undetermined value of the lunar orbit inclination is used to determine whether the lunar orbit inclination convergence requirement is met. If the lunar orbit inclination convergence requirement is not met, the first undetermined value of the lunar orbit inclination is adjusted, and the process returns to the step of determining the undetermined values ​​of the Earth-Moon transfer orbit parameters and the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination; if the lunar orbit inclination convergence requirement is met, the current undetermined values ​​of each parameter, except for the lunar surface working time, are determined as the corresponding target values.

2. The method as described in claim 1, characterized in that, The initial lunar orbit inclination angle, the first undetermined value, is determined based on the target value of the lunar landing point location of the lunar probe and the target value of the lunar probe's working time on the lunar surface.

3. The method as described in claim 1, characterized in that, The Earth-Moon transfer orbit parameters include the probe's entry time into the Earth-Moon transfer orbit and the probe's entry orbit parameters; wherein, the probe's entry orbit parameters include the probe's entry orbit inclination, the probe's entry orbit perigee argument, the probe's entry orbit ascending node longitude, and the probe's entry orbit true perigee angle; The launch trajectory parameters include the launch time of the launch vehicle, the launch azimuth angle of the launch vehicle, and the launch trajectory flight time of the launch vehicle to launch the detector. The process of determining the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined values ​​of the launch trajectory parameters based on the first undetermined value of the lunar orbit inclination angle includes: Obtain the initial, undetermined probe insertion time; Based on the preset correspondence between the probe's orbit insertion time, the design target of the Earth-Moon transfer orbit, and the probe's orbit insertion parameters, the undetermined values ​​of the probe's orbit insertion parameters corresponding to the undetermined value of the probe's orbit insertion time are determined; wherein, the design target of the lunar orbit inclination angle in the design target of the Earth-Moon transfer orbit is the first undetermined value of the lunar orbit inclination angle; it is determined whether the undetermined value of the longitude of the ascending node of the probe's orbit insertion meets the preset range of longitude of the ascending node of the launch vehicle's orbit insertion. If the undetermined longitude of the ascending node of the probe's orbit does not meet the longitude range of the ascending node of the launch vehicle's orbit, then the undetermined value of the probe's orbit entry time is adjusted, and the step of determining the undetermined value of the probe's orbit entry parameters corresponding to the undetermined value of the probe's orbit entry time is returned based on the preset correspondence between the probe's orbit entry time and the probe's orbit entry parameters. If the undetermined longitude of the ascending node of the probe's entry orbit meets the preset range of the ascending node longitude of the launch vehicle's entry orbit, then the range of undetermined values ​​of the launch vehicle's entry orbit inclination angle to which the undetermined value of the probe's entry orbit inclination angle belongs is determined according to the preset set of launch vehicle entry orbit inclination angles. Based on the preset correspondence between the launch vehicle's entry trajectory inclination angle and the launch vehicle's gliding trajectory time, the undetermined range of values ​​for the launch vehicle's gliding trajectory time corresponding to the undetermined range of values ​​for the launch vehicle's entry trajectory inclination angle is determined. Based on the preset correspondence between the perigee argument of the launch vehicle's entry trajectory and the launch vehicle's taxiing trajectory time, the range of undetermined values ​​for the perigee argument of the launch vehicle's entry trajectory corresponding to the undetermined range of values ​​for the launch vehicle's taxiing trajectory time is determined. Determine whether the undetermined value of the perigee angle of the probe's orbital insertion is within the range of undetermined values ​​for the perigee angle of the launch vehicle's orbital insertion; if the undetermined value of the perigee angle of the probe's orbital insertion is not within the range of undetermined values ​​for the perigee angle of the launch vehicle's orbital insertion, then adjust the undetermined value of the probe's orbital insertion time, and return to the step of determining the undetermined value of the probe's orbital parameters corresponding to the undetermined value of the probe's orbital insertion time based on the preset correspondence between the probe's orbital insertion time and the probe's orbital parameters. If the undetermined value of the perigee angle of the probe's orbital entry is within the range of the undetermined value of the perigee angle of the launch vehicle's orbital entry, then the undetermined value of the launch vehicle's orbital trajectory time is determined based on the range of the undetermined value of the perigee angle of the launch vehicle's orbital entry, the range of the undetermined value of the launch vehicle's gliding trajectory time, and the undetermined value of the perigee angle of the probe's orbital entry. The longitude of the ascending node of the launch vehicle's entry track is determined based on the undetermined range of the launch vehicle's inclination angle, the undetermined range of the launch vehicle's gliding trajectory time, and the undetermined value of the launch vehicle's gliding trajectory time. Based on the preset correspondence between the longitude of the ascending node and the orbit insertion time, the orbit insertion time deviation value is determined according to the undetermined longitude of the ascending node of the probe's orbit insertion trajectory and the undetermined longitude of the ascending node of the launch vehicle's orbit insertion trajectory; wherein, the orbit insertion time deviation value is the difference between the undetermined orbit insertion time value of the probe corresponding to the undetermined longitude of the ascending node of the probe's orbit insertion trajectory and the undetermined orbit insertion time value of the launch vehicle corresponding to the undetermined longitude of the ascending node of the launch vehicle's orbit insertion trajectory. Determine whether the orbit insertion time deviation is less than a set deviation threshold; if not, adjust the undetermined value of the probe orbit insertion time and return to the step of determining the undetermined value of the probe orbit insertion parameters corresponding to the undetermined value of the probe orbit insertion time based on the preset correspondence between the probe orbit insertion time and the probe orbit insertion trajectory parameters; if satisfied, determine the undetermined value of the launch vehicle trajectory flight time based on the preset correspondence between the launch vehicle orbit insertion trajectory inclination angle and the launch vehicle ballistic flight time, according to the undetermined value of the probe orbit insertion trajectory inclination angle, the undetermined value range of the launch vehicle orbit insertion trajectory inclination angle, the undetermined value of the launch vehicle gliding trajectory time, and the value range of the launch vehicle gliding trajectory time. The launch time of the launch vehicle is determined based on the undetermined value of the launch vehicle's ballistic flight time and the undetermined value of the probe's orbital insertion time. Based on the preset correspondence between the launch azimuth angle of the launch vehicle, the inclination angle of the launch vehicle's orbital entry, and the time of the launch vehicle's gliding trajectory, the undetermined value of the launch azimuth angle of the launch vehicle is determined according to the undetermined value of the probe's orbital entry inclination angle, the undetermined range of the launch vehicle's orbital entry inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time. Based on the preset correspondence between the probe's true perimeter angle, the launch vehicle's inclination angle, and the launch vehicle's gliding trajectory time, the undetermined value of the probe's true perimeter angle is determined according to the undetermined value of the probe's inclination angle, the undetermined range of the launch vehicle's inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time.

4. The method as described in claim 1, characterized in that, The lunar orbits include, in sequence, a first lunar orbit, a second lunar orbit, a third lunar orbit, and a fourth lunar orbit; The first lunar orbit parameters include the shape parameters of the first lunar orbit and the first lunar flight control parameters for the lunar probe when switching from the Earth-Moon transfer orbit to the first lunar orbit. The second lunar orbit parameters include: the shape parameters of the second orbit change segment, the corresponding lunar second flight control parameters for the second orbit change segment, and the shape parameters of the second circular segment. The parameters of the third lunar orbit include: the shape parameters of the third orbit change segment, the corresponding lunar third flight control parameters of the third orbit change segment, and the shape parameters of the third circular segment. The step of determining the undetermined values ​​of lunar orbit parameters, excluding the undetermined value of the first orbital period, based on the undetermined values ​​of the Earth-Moon transfer orbit parameters, the undetermined value of the first orbital period of the first lunar orbit, and the undetermined value of the second lunar orbital inclination, includes: Based on the undetermined values ​​of the Earth-Moon transfer orbit parameters and the undetermined value of the first orbital period of the first lunar orbit, determine the undetermined values ​​of the shape parameters of the first lunar orbit, excluding the undetermined value of the first orbital period. The undetermined values ​​of the first lunar orbit shape parameters are determined based on the undetermined values ​​of the first lunar orbital shape parameters. Based on the undetermined values ​​of the first lunar orbit parameters and the target values ​​of the second lunar orbit constraint parameters, the undetermined values ​​of the shape parameters of the second orbit change segment are determined, and based on the undetermined values ​​of the shape parameters of the second orbit change segment, the undetermined values ​​of the second lunar flight control parameters and the undetermined values ​​of the shape parameters of the second circular segment are determined. The undetermined values ​​of the second lunar orbit parameters and the target values ​​of the third lunar orbit constraint parameters are determined based on the undetermined values ​​of the shape parameters of the third orbit change segment. The undetermined values ​​of the third lunar orbit flight control parameters and the undetermined values ​​of the shape parameters of the third orbit change segment are then determined based on the undetermined values ​​of the shape parameters of the third orbit change segment. The undetermined value of the fourth lunar orbit parameter is determined based on the second undetermined value of the lunar orbit inclination angle, the target value of the lunar landing point position, the target value of the powered descent orbit parameter, the target value of the fourth lunar orbit constraint parameter, and the undetermined value of the third lunar orbit parameter. Among them, the second lunar orbit constraint parameters are some of the pre-selected parameters from the second lunar orbit parameters, the third lunar orbit constraint parameters are some of the pre-selected parameters from the third lunar orbit parameters, and the fourth lunar orbit constraint parameters are some of the pre-selected parameters from the fourth lunar orbit parameters.

5. The method as described in claim 1, characterized in that, If the landing point deviation requirement is not met, the first orbital period predetermined value is adjusted, including: The undetermined value of the lunar landing point position is determined based on the undetermined value of the lunar orbit parameters. The orbital period adjustment amount is determined based on the undetermined value of the lunar landing point position and the target value of the lunar landing point position. The adjusted first orbital period undetermined value is determined based on the current first orbital period undetermined value and the orbital period adjustment amount.

6. The method as described in claim 3, characterized in that, The method for determining the undetermined range of values ​​for the perigee argument of the launch vehicle's orbit, based on the preset correspondence between the launch vehicle's orbital perigee argument and its taxiing trajectory time, includes: The perigee argument trajectory matrix is ​​obtained. The perigee argument trajectory matrix is ​​determined based on multiple sets of first launch vehicle orbit parameters. The first launch vehicle orbit parameters include the launch vehicle orbit inclination, the launch vehicle glide trajectory time, and the launch vehicle orbit perigee argument. The launch vehicle orbit corresponding to the first launch vehicle orbit parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the perigee argument trajectory matrix, a grid interpolation method is used to process each launch vehicle's taxiing trajectory time value within the undetermined range of the launch vehicle's taxiing trajectory time, thereby determining the undetermined range of the perigee argument of the launch vehicle's orbital insertion trajectory corresponding to the undetermined range of the launch vehicle's taxiing trajectory time.

7. The method as described in claim 3, characterized in that, The process of determining the undetermined longitude of the ascending node of the launch vehicle's orbit based on the undetermined range of the launch vehicle's orbital inclination angle, the undetermined range of the launch vehicle's taxiing trajectory time, and the undetermined value of the launch vehicle's taxiing trajectory time includes: The ascending node trajectory matrix is ​​obtained, which is determined based on multiple sets of second launch vehicle orbital parameters. The second launch vehicle orbital parameters include the launch vehicle orbital inclination, the launch vehicle glide trajectory time, and the ascending node longitude of the launch vehicle orbital. The launch vehicle orbital corresponding to the second launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the ascending node trajectory matrix, the longitude of the ascending node of the launch vehicle's entry trajectory is determined using a grid interpolation method according to the range of the launch vehicle's orbital inclination angle, the range of the launch vehicle's taxiing trajectory time, and the undetermined value of the launch vehicle's taxiing trajectory time.

8. The method as described in claim 3, characterized in that, The method of determining the undetermined value of the launch vehicle's ballistic flight time based on the preset correspondence between the launch vehicle's orbital inclination angle and its ballistic flight time, according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time, includes: The launch vehicle's ballistic flight time trajectory matrix for launching the lunar probe is obtained. This ballistic flight time trajectory matrix is ​​determined based on multiple sets of third launch vehicle orbital parameters, which include the launch vehicle's orbital inclination, the launch vehicle's glide trajectory time, and the launch vehicle's ballistic flight time. The launch vehicle's orbital trajectory corresponding to these third launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit corresponding to the lunar probe. Based on the launch vehicle's ballistic flight time trajectory matrix, the undetermined value of the launch vehicle's ballistic flight time is determined using a grid interpolation method according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's taxiing trajectory time, and the range of the launch vehicle's taxiing trajectory time.

9. The method as described in claim 3, characterized in that, The method of determining the undetermined launch azimuth angle based on the preset correspondence among the launch vehicle launch azimuth angle, the launch vehicle orbit inclination angle, and the launch vehicle coasting trajectory time, according to the undetermined value of the probe orbit inclination angle, the undetermined range of the launch vehicle orbit inclination angle, the undetermined value of the launch vehicle coasting trajectory time, and the range of the launch vehicle coasting trajectory time, includes: The launch azimuth trajectory matrix of the launch vehicle is obtained. The launch azimuth trajectory matrix of the launch vehicle is determined based on multiple sets of fourth launch vehicle orbital parameters. The fourth launch vehicle orbital parameters include the launch vehicle orbital inclination, the launch vehicle glide trajectory time, and the launch vehicle launch azimuth. The launch vehicle orbital corresponding to the fourth launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the launch vehicle launch azimuth trajectory matrix, the undetermined launch azimuth is determined using a grid interpolation method according to the undetermined value of the probe's orbital inclination, the undetermined range of the launch vehicle's orbital inclination, the undetermined value of the launch vehicle's coasting trajectory time, and the range of the launch vehicle's coasting trajectory time.

10. The method as described in claim 3, characterized in that, The method of determining the undetermined value of the true anomaly angle of the launch vehicle's orbit based on the preset correspondence among the launch vehicle's orbital true anomaly angle, the launch vehicle's orbital inclination angle, and the launch vehicle's gliding trajectory time, according to the undetermined value of the probe's orbital inclination angle, the undetermined range of the launch vehicle's orbital inclination angle, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time, includes: The true anomaly trajectory matrix of the launch vehicle's orbital insertion is obtained. This true anomaly trajectory matrix is ​​determined based on multiple sets of fifth launch vehicle orbital parameters. The fifth launch vehicle orbital parameters include the launch vehicle orbital inclination, the launch vehicle's gliding trajectory time, and the true anomaly angle of the launch vehicle orbital insertion. The launch vehicle orbital corresponding to the fifth launch vehicle orbital parameters is connected to the Earth-Moon transfer orbit of the lunar probe. Based on the true perimeter trajectory matrix of the launch vehicle's entry trajectory, the undetermined value of the true perimeter of the launch vehicle's entry trajectory is determined using a grid interpolation method according to the undetermined value of the probe's entry trajectory inclination, the undetermined range of the launch vehicle's entry trajectory inclination, the undetermined value of the launch vehicle's gliding trajectory time, and the range of the launch vehicle's gliding trajectory time.

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