Transfer orbit parameter optimization selection method for lunar large elliptical frozen orbit

Abstract

The invention discloses a transfer orbit parameter optimization selection method for a lunar large elliptical frozen orbit, and belongs to the technical field of deep space exploration orbits. The method comprises the steps that parameters capable of being optimally designed in the lunar large ellipse frozen orbit transfer process are set; analyzing the influence of different capture orbit perilunar heights, inclination angles and periods on speed increment, measurement and control conditions and orbit safety; analyzing the influence of different transition orbit perilunar heights, inclination angles and perilunar arguments on speed increment, measurement and control conditions and orbit safety; and analyzing the influence of different task orbit periods on the speed increment and the orbit safety, if the speed increment and the orbit safety are both optimal, ending the transfer orbit parameter optimization, and if not, selecting the task orbit period through offset parameter optimization. According to the method, a complete target orbit capturing scheme can be obtained, and orbit parameters of a large elliptical frozen orbit captured from the moon can be efficiently designed.

Description

Technical Field

[0001] The invention belongs to the technical field of deep space exploration orbits, and in particular relates to a method for optimizing the transfer orbit parameters of a large elliptical frozen orbit around the moon. Background Art

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

[0003] At present, the theories, models and methods for the design of Earth-Moon transfer orbits and the corresponding orbital design of the lunar large elliptical frozen orbit have been quite complete. However, due to the dynamics of Earth-Moon space, the Earth-Moon transfer orbit cannot directly reach the large elliptical frozen orbit, and there is currently no systematic research on the optimization of transfer orbit parameters from lunar capture to the target circumlunar large elliptical frozen orbit. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for optimizing the transfer orbit parameters of a large elliptical frozen orbit around the moon. By biasing the relevant orbital parameters of the transfer to the large elliptical frozen orbit around the moon as the basis for optimizing the orbital parameters, efficient design of the orbital parameters from lunar capture to the large elliptical frozen orbit can be achieved.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for optimizing transfer orbit parameters of a large elliptical frozen orbit around the moon, comprising the following steps:

[0007] Step 1: Set the parameters that can be optimized during the transfer process of the lunar elliptical frozen orbit, including the capture orbit perigee height, inclination, and period, the transition orbit perigee height, inclination, perigee argument, and the mission orbit period;

[0008] The process of transferring to the frozen orbit of the lunar ellipse includes starting from the Earth and transferring to the perigee to capture the moon and enter the capture orbit, recursively moving to the apogee to maneuver to the transition orbit, and recursively moving to the perigee to maneuver down to the mission orbit, i.e. the frozen orbit of the lunar ellipse; the apogee maneuver requires measurement and control support;

[0009] In order to minimize the total velocity increment of the orbit control maneuver, have measurement and control support during the apogee maneuver, and avoid collision with the moon during the orbit around the moon, the parameters are selected through bias parameter optimization.

[0010] 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; optimize and select capture orbit parameters through bias parameter optimization to achieve optimal velocity increment, measurement and control conditions, and orbit safety;

[0011] Step 2.1: Analyze the impact of different capture orbit perigee heights on velocity increment and orbit safety; the higher the capture orbit perigee height, the greater the capture velocity increment; at the same time, consider the impact of the error generated during the Earth-Moon transfer phase correction and the perigee prediction error on the orbit height, and leave a safe height of 50 km;

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

[0013] Step 2.3: Analyze the impact 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; in order to ensure that the probe does not collide with the moon in the short term when subsequent orbit control is not implemented, there are some restrictions on the capture orbit period;

[0014] Step 2.4: Optimize and select capture orbit parameters based on the analysis results, and determine whether the selected capture orbit parameters can achieve optimal velocity increment, optimal measurement and control conditions, and optimal orbit safety. If so, perform a bias analysis on the possible capture error terms, and analyze whether the lunar capture orbit can be entered under the conditions of other conditions unchanged, perigee height error, capture braking time error, capture startup time error, and capture thrust deviation. If so, proceed to step 3. If not, select the capture orbit parameters through bias parameter optimization.

[0015] Step 3: Optimize and select transition orbit parameters, including analyzing the impact of different transition orbit perigee heights, inclinations, perigee angles on velocity increment, measurement and control conditions, and orbit safety; optimize and select transition orbit parameters through bias parameter optimization to achieve optimal velocity increment, measurement and control conditions, and orbit safety;

[0016] Step 3.1: Analyze the impact of different transition orbit perigee heights on velocity increment, measurement and control conditions, and orbit safety; the higher the transition orbit perigee height, the greater the velocity increment; the transition orbit perigee height has little effect on measurement and control conditions; when the transition orbit perigee height is too low, there is a risk of collision with the moon during the mission;

[0017] Step 3.2: Analyze the impact 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; if the transition orbit inclination is too small, there is a risk of collision with the moon during the mission;

[0018] Step 3.3: Analyze the impact of different transition orbit perigee angles on velocity increment, measurement and control conditions, and orbit safety; the larger the perigee angle, the smaller the velocity increment; when the perigee angle becomes smaller, the measurement and control conditions become better; when the perigee angle is too large, there is a risk of collision with the moon during the mission;

[0019] Step 3.4: Optimize and select transition orbit parameters based on the analysis results, and determine whether the selected transition orbit parameters can achieve optimal speed increment, optimal measurement and control conditions, and optimal orbit safety. If so, proceed to step 4; if not, select transition orbit parameters through bias parameter optimization.

[0020] Step 4: Optimize and select mission orbit parameters, including analyzing the impact of different mission orbit periods on velocity increment and orbit safety; optimize and select mission orbit periods through bias parameter optimization to achieve optimal velocity increment and orbit safety;

[0021] Step 4.1: Analyze the impact of different mission orbital periods on velocity increment and orbital safety; the larger the mission orbital period, the smaller the velocity increment and the greater the risk of lunar collision;

[0022] Step 4.2: Optimize and select the mission orbit period according to the analysis results, and 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.

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

[0024] The present invention first analyzes the impact of capture orbit parameters on velocity increment, measurement and control conditions, and orbital safety, and selects the capture orbit perigee height, inclination, and period through bias parameter optimization; then, the probe enters the transition orbit after maneuvering at the apogee of the capture orbit, and recursively maneuvers to the mission large elliptical frozen orbit of the target period when it reaches the perigee of the transition orbit. Considering the velocity increment, measurement and control conditions, and the risk of impacting the moon, the large elliptical frozen orbit parameters are optimized and selected through bias parameter optimization. The problem of orbital parameter design for reaching the large elliptical frozen orbit is solved through the bias parameters, and a complete capture to target orbit scheme can be obtained, and the orbital parameters from lunar capture to the large elliptical frozen orbit can be efficiently designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a method for optimizing the transfer orbit parameters of a large elliptical frozen orbit around the moon according to the present invention;

[0026] Figure 2 This is the maximum change curve of the perigee angle under different true anomaly angles. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] like Figure 1 As shown, the present invention discloses a method for optimizing the transfer orbit parameters of a large elliptical frozen orbit around the moon, and the specific implementation steps are as follows:

[0029] Step 1: Set the parameters that can be optimized during the transfer process of the lunar elliptical frozen orbit, including the capture orbit perigee height, inclination, and period, the transition orbit perigee height, inclination, perigee argument, and the mission orbit period;

[0030] The process of transferring to the frozen orbit of the lunar ellipse includes starting from the Earth and transferring to the perigee to capture the moon and enter the capture orbit, recursively moving to the apogee to maneuver to the transition orbit, and recursively moving to the perigee to maneuver down to the mission orbit, i.e. the frozen orbit of the lunar ellipse; the apogee maneuver requires measurement and control support;

[0031] In order to minimize the total velocity increment of the orbit control maneuver, have measurement and control support during the apogee maneuver, and avoid collision with the moon during the orbit around the moon, the parameters are selected through bias parameter optimization.

[0032] 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; optimize and select capture orbit parameters through bias parameter optimization to achieve optimal velocity increment, measurement and control conditions, and orbit safety;

[0033] Step 2.1: Analyze the impact of different capture orbit perigee heights on velocity increment and orbit safety; the higher the capture orbit perigee height, the greater the capture velocity increment; at the same time, consider the impact of the error generated during the Earth-Moon transfer phase correction and the perigee prediction error on the orbit height, and leave a safe height of 50 km;

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

[0035] Step 2.3: Analyze the impact 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. The lunar sphere of influence is about 65,000 km, so the capture orbit period is up to 6 days; to ensure that the probe does not collide with the moon in the short term when subsequent orbit control is not implemented, there are some restrictions on the capture orbit period;

[0036] Step 2.4: Optimize and select capture orbit parameters based on the analysis results, and determine whether the selected capture orbit parameters can achieve optimal velocity increment, optimal measurement and control conditions, and optimal orbit safety. If so, perform a bias analysis on the possible capture error terms, and analyze whether the lunar capture orbit can be entered under the conditions of other conditions unchanged, perigee height error, capture braking time error, capture startup time error, and capture thrust deviation. If so, proceed to step 3. If not, select the capture orbit parameters through bias parameter optimization.

[0037] Given a set of parameters, we conduct a pull-off analysis and find out through simulation:

[0038] The same capture braking speed increment, but with a perigee height error of 100 km, can capture the moon;

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

[0040] The moon can be captured if the capture speed increment / power-on time error is under 10%;

[0041] The capture speed increment direction / thrust direction deviation is 5°, which can capture the moon.

[0042] Step 3: Optimize and select transition orbit parameters, including analyzing the impact of different transition orbit perigee heights, inclinations, perigee angles on velocity increment, measurement and control conditions, and orbit safety; optimize and select transition orbit parameters through bias parameter optimization to achieve optimal velocity increment, measurement and control conditions, and orbit safety;

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

[0044] Step 3.2: Analyze the impact 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; if 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 influence of different transition orbit perigee angles on velocity increment, measurement and control conditions, and orbit safety; the large elliptical frozen orbit requires a perigee angle of 90°, while the perigee angle of the Earth-Moon transfer orbit when it reaches the perigee varies between 120° and 150°. When changing orbits at different true perigee angles, the maximum change of the perigee angle (relative value) is as follows: Figure 2 As shown in the figure, it is most efficient to adjust the argument of the perigee by maneuvering near the apogee; the larger the argument of the perigee, the smaller the velocity increment; when the argument of the perigee becomes smaller, the measurement and control conditions become better; when the argument of the 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, and determine whether the selected transition orbit parameters can achieve optimal speed increment, optimal measurement and control conditions, and optimal orbit 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 and select mission orbit periods 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 larger the mission orbital period, the smaller the velocity increment and the greater the risk of lunar collision;

[0049] Step 4.2: Optimize and select the mission orbit period according to the analysis results, and 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 description is only a specific embodiment of the present invention and is 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 the transfer orbit parameters of 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 lunar elliptical frozen orbit, including the capture orbit perigee height, inclination, and period, the transition orbit perigee height, inclination, perigee argument, 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, perigee angles 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 optimal 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 the transfer orbit parameters of a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The transfer process of the lunar elliptical frozen orbit in step 1 includes starting from the Earth and transferring to the perigee to capture the moon and enter the capture orbit, recursively moving to the apogee to maneuver to the transition orbit, and recursively moving to the perigee to maneuver down to the mission orbit, i.e., the lunar elliptical frozen orbit; In order to minimize the total velocity increment of the orbit control maneuver, have measurement and control support during the apogee maneuver, and avoid collision with the moon during the orbit around the moon, the parameters are selected through bias parameter optimization.

3. The method for optimizing the transfer orbit parameters of 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 height of 50 km.

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

5. The method for optimizing the transfer orbit parameters of 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 the transfer orbit parameters of 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, determining whether the selected capture orbit parameters can achieve optimal velocity increment, optimal measurement and control conditions, and optimal orbit safety. If so, performing a bias analysis on possible capture error items, and analyzing whether the lunar capture orbit can be entered 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 the capture orbit parameters through bias parameter optimization.

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

8. The method for optimizing the transfer orbit parameters of a large elliptical frozen orbit around the moon according to claim 1, characterized in that: The step 3 also includes: 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 orbit safety. If so, proceed to step 4. If not, select the transition orbit parameters through bias parameter optimization.

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

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