A method for optimizing the transfer orbit parameters of a large elliptical frozen orbit around the moon

Abstract

The application discloses a transfer orbit parameter optimization selection method of a lunar-circulating large-ellipse frozen orbit and belongs to the technical field of deep space exploration orbits. The method comprises the following steps: setting parameters that can be optimized in a transfer process of a lunar-circulating large-ellipse frozen orbit; analyzing influences of different near-lunar-point altitudes, inclination angles and periods of a capture orbit on velocity increments, measurement and control conditions and orbit safety; analyzing influences of different near-lunar-point altitudes, inclination angles and near-lunar-point amplitude angles of a transition orbit on velocity increments, measurement and control conditions and orbit safety; and analyzing influences of different mission orbit periods on velocity increments and orbit safety. If all are optimal, the optimization of the transfer orbit parameters is ended; if not, a mission orbit period is selected by means of bias parameter optimization. The application can obtain a complete capture-to-target orbit scheme and efficiently design orbit parameters from the moon capture to the large-ellipse frozen orbit.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of deep space exploration orbit, and particularly relates to a transfer orbit parameter optimization selection method of a lunar large elliptical frozen orbit. BACKGROUND

[0002] The lunar large elliptical frozen orbit has been widely applied in lunar exploration missions due to its stable dynamic characteristics and excellent geometric characteristics, and it is a consensus reached by existing research results that the lunar large elliptical frozen orbit is used as a mission orbit type of a lunar relay satellite.

[0003] At present, the theory, model and method of the earth-moon transfer orbit design and the corresponding orbit design of the lunar large elliptical frozen orbit are quite perfect. However, due to the earth-moon space dynamics, the earth-moon transfer orbit cannot directly reach the large elliptical frozen orbit, and there is no systematic research on the optimization selection of the transfer orbit parameters from the lunar capture to the target lunar large elliptical frozen orbit. SUMMARY

[0004] To solve the above technical problems, the application provides a transfer orbit parameter optimization selection method of a lunar large elliptical frozen orbit, which offsets the related orbit parameters of the transfer to the lunar large elliptical frozen orbit as the basis for optimizing and selecting the orbit parameters, so as to efficiently design the orbit parameters from the lunar capture to the large elliptical frozen orbit.

[0005] To achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] A transfer orbit parameter optimization selection method of a lunar large elliptical frozen orbit, comprising the following steps:

[0007] Step 1: setting the parameters that can be optimized and designed in the transfer process of the lunar large elliptical frozen orbit, including the near-moon point height, inclination and period of the capture orbit, the near-moon point height, inclination and near-moon point amplitude angle of the transition orbit, and the period of the mission orbit;

[0008] The transfer process of the lunar large elliptical frozen orbit includes the transfer from the earth to the near-moon point for the lunar capture to enter the capture orbit, the recursion to the far-moon point for the transition to the transition orbit, and the recursion to the near-moon point for the de-orbiting to the mission orbit, i.e. the lunar large elliptical frozen orbit; wherein the far-moon point maneuvering needs the support of the measurement and control;

[0009] In order to minimize the total velocity increment of the orbit control maneuvering, support the measurement and control during the far-moon point maneuvering, and avoid the moon collision during the lunar period, the parameters are optimized and selected by offsetting.

[0010] Step 2: Optimize the selection of the capture orbit parameters, including analyzing the influence of different capture orbit perigee altitudes, inclinations, and periods on the velocity increment, the TT&C conditions, and the orbit safety; and optimizing the selection of the capture orbit parameters through bias parameters to achieve optimal velocity increment, optimal TT&C conditions, and optimal orbit safety.

[0011] Step 2.1: Analyze the influence of different capture orbit perigee altitudes on the velocity increment and the orbit safety; the higher the capture orbit perigee altitude, the greater the capture velocity increment; meanwhile, considering the influence of the error generated during the lunar transfer segment correction and the perigee prediction error on the orbit altitude, a safety altitude of 50 km is left;

[0012] Step 2.2: Analyze the influence of different capture orbit inclinations on the velocity increment and the TT&C conditions; the total velocity increment changes slightly with the capture orbit inclination, but the change is not large; the TT&C conditions become better as the capture orbit inclination increases;

[0013] Step 2.3: Analyze the influence of different capture orbit periods on the velocity increment and the orbit safety; the greater the capture orbit period, the smaller the velocity increment; considering that the capture orbit needs to be within the lunar sphere of influence, the capture orbit period cannot be too large; to ensure that the probe does not collide with the Moon in the short term in the event of no subsequent orbit control, the capture orbit period is limited;

[0014] Step 2.4: Optimize the selection of the capture orbit parameters based on the analysis results, determine whether the selected capture orbit parameters can achieve optimal velocity increment, optimal TT&C conditions, and optimal orbit safety, if so, perform a bias analysis on possible capture error terms, and analyze whether the probe can enter the lunar capture orbit under the conditions of perigee altitude error, capture braking time error, capture on-time error, and capture thrust deviation, if so, proceed to Step 3, if not, optimize the selection of the capture orbit parameters through bias parameters.

[0015] Step 3: Optimize the selection of the transition orbit parameters, including analyzing the influence of different transition orbit perigee altitudes, inclinations, and perigee amplitudes on the velocity increment, the TT&C conditions, and the orbit safety; and optimizing the selection of the transition orbit parameters through bias parameters to achieve optimal velocity increment, optimal TT&C conditions, and optimal orbit safety;

[0016] Step 3.1: Analyze the influence of different transition orbit perigee altitudes on the velocity increment, the TT&C conditions, and the orbit safety; the higher the transition orbit perigee altitude, the greater the velocity increment; the transition orbit perigee altitude has little influence on the TT&C conditions; when the transition orbit perigee altitude is too low, there is a risk of collision with the Moon during the mission;

[0017] Step 3.2: analyze the influence of different transition orbit inclination angles on the velocity increment, the TT&C condition and the orbit safety; the greater the transition orbit inclination angle, the smaller the velocity increment and the better the TT&C condition; when the transition orbit inclination angle is too small, there is a risk of crashing into the moon during the mission;

[0018] Step 3.3: analyze the influence of different transition orbit perigee amplitudes on the velocity increment, the TT&C condition and the orbit safety; the greater the perigee amplitude, the smaller the velocity increment; when the perigee amplitude decreases, the TT&C condition becomes better; when the perigee amplitude is too large, there is a risk of crashing into the moon during the mission;

[0019] Step 3.4: according to the analysis result, the transition orbit parameters are optimized and selected; it is judged whether the selected transition orbit parameters can achieve the optimal velocity increment, the optimal TT&C condition and the optimal orbit safety; if yes, step 4 is entered; if not, the transition orbit parameters are optimized and selected through the bias parameters.

[0020] Step 4: the mission orbit parameters are optimized and selected, including analyzing the influence of different mission orbit periods on the velocity increment and the orbit safety; the mission orbit period is optimized and selected through the bias parameters, so that the optimal velocity increment and the optimal orbit safety are achieved;

[0021] Step 4.1: analyze the influence of different mission orbit periods on the velocity increment and the orbit safety; the greater the mission orbit period, the smaller the velocity increment and the greater the risk of crashing into the moon;

[0022] Step 4.2: according to the analysis result, the mission orbit period is optimized and selected; it is judged whether the selected mission orbit period can achieve the optimal velocity increment and the optimal orbit safety; if yes, the optimized parameters are obtained, and the transfer orbit parameter optimization is ended; if not, the mission orbit period is optimized and selected through the bias parameters.

[0023] The beneficial effects of the present application are:

[0024] The present application firstly analyzes the influence of the capture orbit parameters on the velocity increment, the TT&C condition and the orbit safety; the capture orbit perigee height, the inclination and the period are optimized and selected through the bias parameters; then, the probe enters the transition orbit after being maneuvered at the capture orbit apogee, and is maneuvered to the target period mission large ellipse frozen orbit at the transition orbit perigee. Considering the velocity increment, the TT&C condition and the risk of crashing into the moon, the large ellipse frozen orbit parameters are optimized and selected through the bias parameters. The problem of designing the orbit parameters for reaching the large ellipse frozen orbit is solved through the bias parameters, a complete capture-to-target orbit scheme can be obtained, and the orbit parameters from the moon capture to the large ellipse frozen orbit can be efficiently designed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a principle diagram of the transfer orbit parameter optimization method of the large ellipse frozen orbit around the moon of the present application;

[0026] Figure 2 The maximum change curve of the perilune amplitude angle under different variable orbit true anomaly angles. DETAILED DESCRIPTION

[0027] The application will be further described below in conjunction with the accompanying drawings and examples.

[0028] As shown in the drawings, Figure 1 The method for optimizing and selecting the transfer orbit parameters of the circumlunar large-elliptical frozen orbit disclosed by the application comprises the following specific implementation steps:

[0029] Step 1: Setting the parameters that can be optimized and designed in the transfer process of the circumlunar large-elliptical frozen orbit, including the perilune height, inclination and period of the capture orbit, the perilune height, inclination and perilune amplitude angle of the transition orbit, and the period of the mission orbit;

[0030] The transfer process of the circumlunar large-elliptical frozen orbit comprises the following steps: transferring from the earth to the perilune to perform the moon capture to enter the capture orbit, recursively transferring to the apolune to perform the apolune maneuver to the transition orbit, and recursively transferring to the perilune to perform the deorbit maneuver to the mission orbit, i.e., the circumlunar large-elliptical frozen orbit; wherein the apolune maneuver needs the support of the measurement and control;

[0031] In order to minimize the total velocity increment of the orbit control maneuver, support the apolune maneuver by the measurement and control, and avoid the moon collision during the circumlunar period, the parameters are optimized and selected by biasing.

[0032] Step 2: Optimizing and selecting the capture orbit parameters, including analyzing the influence of different capture orbit perilune heights, inclinations and periods on the velocity increment, the measurement and control conditions and the orbit safety; optimizing and selecting the capture orbit parameters by biasing to achieve the optimization of the velocity increment, the measurement and control conditions and the orbit safety;

[0033] Step 2.1: Analyzing the influence of different capture orbit perilune heights on the velocity increment and the orbit safety; the higher the capture orbit perilune height is, the greater the capture velocity increment is; at the same time, considering the influence of the error generated during the earth-moon transfer segment correction and the perilune prediction error on the orbit height, a safety height of 50 km is left;

[0034] Step 2.2: Analyzing the influence of different capture orbit inclinations on the velocity increment and the measurement and control conditions; the total velocity increment slightly changes but the change amplitude is not large when the capture inclination is different; the measurement and control conditions become better when the capture inclination increases;

[0035] Step 2.3: Analyze the influence of different capture orbit periods on velocity increment and orbit safety; the larger the capture orbit period, the smaller the velocity increment; considering that the capture orbit needs to be within the lunar sphere of influence, the capture orbit period cannot be too large, and the lunar sphere of influence is about 65,000 km, so the longest capture orbit period is 6 days; to ensure that the probe does not collide with the Moon in the short term if subsequent orbit control is not implemented, the capture orbit period is limited;

[0036] Step 2.4: Optimize the selection of capture orbit parameters based on the analysis results, determine whether the selected capture orbit parameters can achieve optimal velocity increment, optimal measurement and control conditions, and optimal orbit safety; if so, perform bias analysis on possible capture error terms, and analyze whether the probe can enter the lunar capture orbit under the conditions of near-lunar point height error, capture braking time error, capture on-time error, and capture thrust deviation, respectively, if the other conditions remain unchanged; if so, proceed to Step 3, if not, optimize the selection of capture orbit parameters by biasing parameters.

[0037] Given a set of parameters, bias analysis is performed, and simulation shows that:

[0038] The same capture braking velocity increment, but with a near-lunar point height error of 100 km, can capture the Moon;

[0039] The same capture braking velocity increment, but with a braking time error of 90 s, can capture the Moon;

[0040] Capture velocity increment / on-time error is 10%, which can capture the Moon;

[0041] Capture velocity increment direction / thrust direction deviation is 5°, which can capture the Moon.

[0042] Step 3: Optimize the selection of transition orbit parameters, including analyzing the influence of different transition orbit near-lunar point heights, inclinations, and near-lunar point amplitudes on velocity increment, measurement and control conditions, and orbit safety; optimize the selection of transition orbit parameters by biasing parameters to achieve optimal velocity increment, optimal measurement and control conditions, and optimal orbit safety;

[0043] Step 3.1: Analyze the influence of different transition orbit near-lunar point heights on velocity increment, measurement and control conditions, and orbit safety; the higher the transition orbit near-lunar point height, the greater the velocity increment; the transition orbit near-lunar point height has little effect on measurement and control conditions; when the transition orbit near-lunar point height is too low, there is a risk of collision with the Moon during the mission;

[0044] Step 3.2: Analyze the influence of different transition orbit inclinations on velocity increment, measurement and control conditions, and orbit safety; the larger the transition orbit inclination, the smaller the velocity increment and the better the measurement and control conditions; when the transition orbit inclination is too small, there is a risk of collision with the Moon during the mission;

[0045] Step 3.3: Analyze the impact of different transition orbit perigee arguments on velocity increment, measurement and control conditions, and orbit safety. The large elliptical frozen orbit requires a perigee argument of 90°, while the perigee argument of the Earth-Moon transfer orbit when reaching the perigee varies between 120° and 150°. When performing orbit changes at different true perigee angles, the maximum change in the perigee argument (relative value) is as follows: Figure 2 As shown, maneuvers near the aphelion are the most efficient way to adjust the argument of perigee. The larger the argument of perigee, the smaller the velocity increment. As the argument of perigee decreases, the measurement and control conditions improve. When the argument of perigee is too large, there is a risk of collision with the moon during the mission.

[0046] Step 3.4: Optimize and select transition orbit parameters based on the analysis results to determine whether the selected transition orbit parameters can achieve optimal speed increment, optimal measurement and control conditions, and optimal track safety. If so, proceed to step 4. If not, select transition orbit parameters through bias parameter optimization.

[0047] Step 4: Optimize and select mission orbit parameters, including analyzing the impact of different mission orbit periods on velocity increment and orbit safety; optimize the mission orbit period through bias parameter optimization to achieve optimal velocity increment and orbit safety;

[0048] Step 4.1: Analyze the impact of different mission orbital periods on velocity increment and orbital safety. The longer the mission orbital period, the smaller the velocity increment and the greater the risk of lunar impact.

[0049] Step 4.2: Optimize and select the mission orbit period based on the analysis results to determine whether the selected mission orbit period can achieve optimal velocity increment and orbit safety. If so, obtain the optimized parameters and the transfer orbit parameter optimization is completed. If not, select the mission orbit period through bias parameter optimization.

[0050] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon, characterized in that: The following steps are involved: Step 1: Set the parameters that can be optimized during the transfer process of the highly elliptical frozen orbit around the moon, including the capture orbit perihelion altitude, inclination, and period; the transition orbit perihelion altitude, inclination, and argument of perihelion; and the mission orbit period. Step 2: Optimize and select capture orbit parameters, including analyzing the impact of different capture orbit perigee heights, inclinations, and periods on velocity increment, measurement and control conditions, and orbit safety. Determine whether the designed capture orbit parameters can achieve optimal velocity increment, measurement and control conditions, and orbit safety. If so, proceed to Step 3. If not, select capture orbit parameters through bias parameter optimization. Step 3: Optimize and select transition orbit parameters, including analyzing the effects of different transition orbit perigee heights, inclinations, and perigee arguments on velocity increment, measurement and control conditions, and orbit safety. Determine whether the designed transition orbit parameters can achieve optimal velocity increment, measurement and control conditions, and orbit safety. If so, proceed to Step 4. If not, select transition orbit parameters through bias parameter optimization. Step 4: Optimize and select mission orbit parameters, including analyzing the impact of different mission orbit periods on velocity increment and orbit safety; determine whether the designed mission orbit period can achieve optimal velocity increment and orbit safety. If so, obtain the optimized parameters and the transfer orbit parameter optimization is completed. If not, select the mission orbit period through bias parameter optimization.

2. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The process of transferring to a highly elliptical frozen orbit around the moon in step 1 includes starting from the Earth and transferring to the perigee to capture the moon into a capture orbit, recursively maneuvering to the apogee to a transition orbit, and recursively maneuvering to the perigee to descend to the mission orbit, i.e., a highly elliptical frozen orbit around the moon; In order to minimize the total velocity increment of the orbit control maneuver, ensure the support of TT&C during the apogee maneuver, and avoid the lunar collision during the orbit, the parameters are selected through bias parameter optimization.

3. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 2 includes analyzing the impact of different capture orbit perigee heights on velocity increment and orbit safety, including: the higher the capture orbit perigee height, the greater the capture velocity increment, and setting a safety altitude of 50 km.

4. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 2 also includes analyzing the effects of different capture orbit inclinations on velocity increment and measurement and control conditions, including: different capture inclinations result in a small change in the total velocity increment; the larger the capture inclination, the better the measurement and control conditions.

5. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 2 also includes analyzing the impact of different capture orbit periods on speed increment and orbit safety, including: the larger the capture orbit period, the smaller the speed increment.

6. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 2 also includes optimizing and selecting capture orbit parameters, judging whether the selected capture orbit parameters can achieve optimal velocity increment, optimal measurement and control conditions, and optimal orbit safety. If so, performing bias analysis on possible capture error items, analyzing whether it is possible to enter the lunar capture orbit under the conditions of other conditions remaining unchanged, perigee height error, capture braking time error, capture startup duration error, and capture thrust deviation. If so, proceed to step 3; if not, selecting capture orbit parameters through bias parameter optimization.

7. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 3 includes: Step 3.1: Analyze the impact of different transition orbit perigee heights on velocity increment, tracking and control conditions, and orbital safety. The analysis includes the following: The higher the transition orbit perigee height, the greater the velocity increment; the transition orbit perigee height does not affect tracking and control conditions; and the lower the transition orbit perigee height, the higher the risk of lunar impact during the mission. Step 3.2: Analyze the impact of different transition orbit inclinations on velocity increment, tracking and control conditions, and orbital safety. The analysis includes the following: The larger the transition orbit inclination, the smaller the velocity increment, the better the tracking and control conditions, and the lower the risk of lunar impact during the mission. Step 3.3: Analyze the impact of different transition orbit perigee arguments on velocity increment, tracking and control conditions, and orbital safety, including: the larger the perigee argument, the smaller the velocity increment, the worse the tracking and control conditions, and the higher the risk of lunar collision during the mission.

8. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 3 further comprises: Step 3.4: Optimize and select the transition orbit parameters to determine whether the selected transition orbit parameters can achieve optimal speed increment, optimal measurement and control conditions, and optimal track safety. If so, proceed to step 4. If not, select the transition orbit parameters through bias parameter optimization.

9. The method for optimizing transfer orbit parameters for a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 4 comprises: Step 4.1: Analyze the impact of different mission orbital periods on velocity increment and orbital safety, including: the larger the mission orbital period, the smaller the velocity increment and the greater the risk of lunar collision.

10. The method for optimizing transfer orbit parameters of a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 4 further comprises: Step 4.2: Optimizing and selecting the mission orbit period includes: determining whether the selected mission orbit period can achieve optimal velocity increment and optimal orbit safety. If so, the optimized parameters are obtained and the transfer orbit parameter optimization is completed. If not, the mission orbit period is selected through bias parameter optimization.

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