Design method of lunar global positioning constellation based on earth-moon space dro reference orbit

Abstract

The application relates to a design method of a moon global positioning constellation based on a lunar space DRO reference orbit, wherein the initial orbit state and the orbit period of any DRO reference orbit in a DRO reference orbit to be deployed are determined based on the initial phase of the DRO reference orbit; the initial orbit state of any satellite to be deployed on the initial phase of the DRO reference orbit is determined based on the orbit state corresponding to the target phase; the orbit period of the any satellite is determined based on the orbit period of the any DRO reference orbit; the target orbit state corresponding to the any satellite is obtained based on the orbit period of the any satellite and the initial orbit state of the any satellite; and the moon global positioning constellation under a four-body model is constructed based on the target orbit state corresponding to each satellite. The moon global positioning constellation constructed by the application has higher stability and higher moon surface coverage capacity compared with the existing near-moon constellation.

Description

Technical Field

[0001] This invention relates to the field of lunar global positioning constellation design technology, and in particular to a lunar global positioning constellation design method based on the Earth-Moon space DRO reference orbit. Background Technology

[0002] Similar to building a global positioning satellite constellation for Earth orbit (such as GPS and BeiDou), building a lunar global positioning constellation for lunar orbit can provide real-time positioning and timing services for users on the lunar surface, thereby enhancing their ability to operate on the lunar surface.

[0003] Currently, although a lunar global positioning constellation based on a distant retrograde orbit (DRO) in the Earth-Moon space can be constructed using a three-body model, the problem of how to construct a lunar global positioning constellation based on the DRO in a four-body model that can operate stably for several years and meet the requirements of high lunar surface coverage has not yet been solved. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a lunar global positioning constellation design method based on the DRO reference orbit of the Earth and Moon, which can construct a lunar global positioning constellation that can operate stably for several years and meet the requirements of high lunar surface coverage based on the DRO reference orbit and a four-body model.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] This invention provides a method for designing a lunar global positioning constellation based on a DRO (Digital Orbital Response) reference orbit in the Earth-Moon space. In this method, based on the initial phase of any DRO reference orbit to be deployed, the initial orbital state and orbital period of that DRO reference orbit are determined. For any satellite to be deployed in any DRO reference orbit with an initial phase of a target phase, the initial orbital state of that satellite is determined based on the orbital state corresponding to the target phase. The orbital period of that satellite is determined based on the orbital period of the DRO reference orbit. Based on the orbital period and the initial orbital state of that satellite, the target orbital state corresponding to that satellite is obtained. Based on the target orbital state of each satellite, a lunar global positioning constellation based on a four-body model is constructed.

[0007] The beneficial effects of this invention are: it provides a lunar global positioning constellation design method based on the Earth-Moon Space DRO reference orbit, which can construct a lunar global positioning constellation that can operate stably for several years (at least 3 years) and meet a high (over 98%) lunar surface coverage under a four-body model. Furthermore, each satellite located on the DRO can determine its own orbital position through inter-satellite measurements, achieving autonomous orbit determination without the assistance of lunar surface base stations.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, based on the total number of satellites to be deployed, the number of DRO reference orbits to be deployed is determined. Based on the number of DRO reference orbits to be deployed, the number of DRO reference orbits to be deployed is determined.

[0010] The beneficial effect of adopting the above-mentioned further scheme is that it provides a specific implementation method for determining the number of DRO reference orbits.

[0011] Furthermore, the number of DRO reference orbits to be deployed is P, and the total number of satellites to be deployed is N, where P is a factor of N.

[0012] The beneficial effect of adopting the above-mentioned further scheme is that it provides a correspondence between the number of DRO reference orbits to be deployed and the total number of satellites to be deployed, so that the number of DRO reference orbits can be determined based on the total number of satellites to be deployed.

[0013] Furthermore, based on the total number of satellites to be deployed and the number of DRO reference orbits to be deployed, the number of satellites to be deployed on each DRO reference orbit is determined. Based on the number of satellites deployed on each DRO reference orbit, the initial phase of the satellites deployed on each DRO reference orbit is determined.

[0014] The advantage of adopting the above-mentioned further scheme is that it provides a specific implementation for determining the total number of satellites deployed on each DRO reference orbit.

[0015] Furthermore, the number of satellites deployed on each of the aforementioned DRO reference orbits is Q, where Q = N / P.

[0016] The beneficial effect of adopting the above-mentioned further scheme is that it provides a correspondence between the number of satellites deployed on each DRO reference orbit, the number of DRO reference orbits to be deployed, and the total number of satellites to be deployed, so that the number of satellites deployed on each DRO reference orbit can be determined based on the total number of satellites to be deployed and the number of DRO reference orbits.

[0017] Furthermore, based on the orbital state corresponding to the target phase in the DRO plane under the three-body model, the empirical orbital state corresponding to the target phase is determined. This empirical orbital state is obtained by fixing the z-axis component of the orbital state corresponding to the target phase to the maximum value region corresponding to the orbital period of any DRO reference orbit; the maximum value region is a preset region; the direction of the z-axis is the same as the angular momentum direction of the lunar orbital plane in the four-body model. Based on the differential evolution algorithm, using the empirical orbital state corresponding to the target phase as a variable and the difference between the orbital period of any DRO reference orbit and the target orbital period as the optimization objective, the empirical orbital state corresponding to the target phase is optimized. Based on the optimization result of the empirical orbital state corresponding to the target phase, the initial orbital state of any DRO reference orbit is determined.

[0018] The beneficial effect of adopting the above-mentioned further scheme is that it provides a specific implementation method for determining the initial orbital state of each DRO reference orbit.

[0019] Furthermore, the orbital period of any DRO reference orbit is determined as the orbital period of any satellite.

[0020] The beneficial effect of adopting the above-mentioned further scheme is that, since the orbital period of any satellite is the same as the orbital period of any DRO reference orbit, the orbital periods of each satellite located in the same DRO reference orbit are also the same, and each satellite located in the same DRO reference orbit can fly stably, thereby maintaining a relatively stable geometric configuration.

[0021] Furthermore, based on the initial orbital state of any DRO reference orbit and the target phase, the initial orbital state of any satellite is determined.

[0022] The beneficial effect of adopting the above-mentioned further scheme is that it provides a specific way to determine the initial orbital state of each satellite.

[0023] Furthermore, based on the differential evolution algorithm, the initial orbital state of any satellite is used as a variable, and the difference between the orbital period of any satellite and the target orbital period is used as the optimization objective to optimize the initial orbital state of any satellite, thereby obtaining the target orbital state of any satellite.

[0024] The beneficial effect of adopting the above-mentioned further scheme is that it provides a specific way to determine the target orbit status of each satellite on each DRO reference orbit.

[0025] Furthermore, Q satellites are evenly deployed on each of the aforementioned DRO reference orbits.

[0026] The beneficial effect of adopting the above-mentioned further scheme is that, since the satellites are evenly distributed on the same DRO reference orbit, each satellite can maintain stable flight, thereby maintaining a relatively stable geometric configuration. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the lunar global positioning constellation design method based on the Earth-Moon space DRO reference orbit provided by the present invention.

[0028] Figure 2 This is a schematic diagram illustrating the configuration of a lunar global positioning constellation deployed based on the Earth-Moon space DRO reference orbit, as provided by the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of this application are described below with reference to the accompanying drawings. In the description of the embodiments of this application, the terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to limit the application. As used in the specification and appended claims of this application, the singular expressions "a," "the," "the," "the," and "this" are intended to also include expressions such as "one or more," unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of this application, "at least one" and "one or more" refer to one or more (including two). The term "and / or" is used to describe the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0030] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. The term "connection" includes direct connections and indirect connections, unless otherwise stated. "First" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0031] In the embodiments of this application, the words "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of the words "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0032] To facilitate understanding of the technical solutions of the embodiments of this application by those skilled in the art, the technical terms involved in the embodiments of this application will be explained below.

[0033] DRO baseline orbit: refers to the trajectory of a retrograde orbit traveling a long distance in the Earth-Moon space within one cycle.

[0034] Circular restricted three-body model (abbreviated as three-body model): refers to a dynamic system model consisting of the Earth, the Moon and a spacecraft.

[0035] Double-circle restricted four-body model (abbreviated as four-body model): refers to a dynamic system model consisting of the sun, earth, moon and spacecraft.

[0036] Dimensional lunar-centered rotating coordinate system: This refers to a coordinate system whose origin is located at the center of mass of the moon, with the positive x-axis pointing from the center of mass of the earth to the center of mass of the moon, the positive z-axis aligned with the angular momentum direction of the orbital plane of the earth or moon in the four-body model, and the y-axis perpendicular to both the x-axis and z-axis, forming a right-handed coordinate system.

[0037] Orbital state: refers to a six-dimensional vector consisting of three-dimensional position and three-dimensional velocity. The unit of position is kilometers (km), and the unit of velocity is kilometers per second (km / s). The coordinate system adopted is a dimensionless lunar rotating coordinate system. Phase of DRO orbital state: refers to the angle between the projection vector of the orbital state's position vector onto the xy plane of the dimensionless lunar rotating coordinate system and the positive x-axis of the coordinate system.

[0038] Initial phase of DRO orbital state: refers to the phase corresponding to the initial state of the DRO orbital.

[0039] The orbital period of the DRO reference orbit under the four-body model refers to the ratio of the total propagation time of the DRO reference orbit to the total number of angles the trajectory rotates through in the dimensionless lunar rotating coordinate system xy plane.

[0040] The orbital stability of the DRO reference orbit is associated with the trajectory of the DRO reference orbit, which is obtained by intersecting the xy plane of a dimensionless lunar rotating coordinate system with equal phase angle intervals. Each intersecting plane has several intersection points with the DRO reference orbit. The maximum distance between two points on the intersecting plane is called the width of the intersecting plane, and the average value of all the intersecting plane widths can be defined as the orbital stability.

[0041] A satellite constellation refers to a group of artificial satellites working together as a unified system, also known as a distributed satellite system. Unlike a single satellite, a Global Positioning Satellite constellation can provide permanent global (or near-global) coverage, ensuring that at any given point on Earth, at least four satellites are visible at any given time. The satellites are typically placed in complementary orbital planes and can connect with distributed ground stations. Inter-satellite communication technology can also be used to exchange information with each satellite in the constellation.

[0042] Similar to building a global positioning satellite constellation for Earth orbit (such as GPS and BeiDou), building a lunar global positioning constellation for lunar orbit can provide real-time positioning and timing services for users on the lunar surface, thereby enhancing their ability to operate on the lunar surface.

[0043] Currently, a lunar global positioning constellation targeting the lunar orbit can be constructed based on at least one of the lunar orbit, the Earth-Moon libration point Halo orbit, and the Earth-Moon space DRO reference orbit.

[0044] While near-lunar orbits are relatively stable, allowing satellites in these orbits to communicate with targets on the Moon at close range, building a lunar global positioning constellation based on near-lunar orbits would require a large number of satellites to cover most of the lunar surface (e.g., 20 satellites in near-lunar circular orbits could achieve 100% lunar surface coverage). Furthermore, satellites in near-lunar orbits cannot perform autonomous orbit determination.

[0045] Furthermore, while the Halo orbit, based on the Earth-Moon libration point, can achieve the same level of lunar surface coverage as a near-lunar orbit with a smaller number of satellites (e.g., 99% lunar surface coverage can be achieved using 16 satellites), the Halo orbit is an unstable three-body orbit. Therefore, when constructing a lunar global positioning constellation based on the Halo orbit targeting the lunar orbit, the satellites located in the Halo orbit require frequent position-keeping pulses.

[0046] Addressing the limitations of near-lunar orbits in achieving autonomous orbit determination and the need for frequent position-keeping pulses in Halo orbits (Earth-Moon translational point orbits), the DRO (Digital Orbital Reference) can overcome these shortcomings to some extent due to its inherent dynamic characteristics. The DRO reference orbit is a stable periodic orbit in the circular restricted three-body problem. Theoretically, a spacecraft in a DRO reference orbit can operate for 100 years, and in ephemeris models, it can remain stably stationary for at least 30 years. Therefore, when constructing a lunar global positioning constellation based on the DRO reference orbit for lunar orbit, the position-keeping pulse frequency of DRO satellites can be reduced to once every few years. Furthermore, autonomous orbit determination of satellites located on the DRO is possible based on the theory of gravitational field asymmetry. Therefore, the DRO is a relatively ideal orbit for constructing a lunar global positioning constellation for lunar orbit.

[0047] Currently, while a lunar global positioning constellation with high lunar coverage can be constructed within tens of days using the DRO model under the three-body model, the problem of how to construct a DRO lunar global positioning constellation that can operate stably for several years and meet the requirement of high lunar surface coverage under the four-body model remains unsolved.

[0048] To address the aforementioned problem of constructing a DRO lunar global positioning constellation that can operate stably for several years and meet the requirement of high lunar surface coverage under the four-body model, this application provides a lunar global positioning constellation design method based on the Earth-Moon space DRO reference orbit, which can construct a lunar global positioning constellation that can operate stably for several years (at least 3 years) and meet the requirement of high lunar surface coverage (above 98%) under the four-body model.

[0049] See Figure 1 The lunar global positioning constellation design method based on the Earth-Moon space DRO reference orbit provided by this invention includes the following steps S101-S105:

[0050] S101: Based on the initial phase of the target DRO reference orbit, determine the initial orbit state and orbit period of the target DRO reference orbit.

[0051] The target DRO reference orbit can be any of the DRO reference orbits to be deployed.

[0052] In some embodiments, the number of DRO reference orbits to be deployed is constrained by the total number of satellites to be deployed, and, in order to cover the high-latitude regions of the Moon, the amplitude of the Z-axis of the DRO reference orbits should be as large as possible. For example, if a DRO reference orbit with a period of 7.38 days and stable for 3 years is constructed under a four-body model, the amplitude of its Z-axis can reach 20,000 kilometers. Therefore, the DRO reference orbits to be deployed can be determined based on the following:

[0053] Based on the total number of satellites to be deployed, the number of DRO reference orbits to be deployed is determined. Furthermore, based on the number of DRO reference orbits to be deployed, the specific DRO reference orbits to be deployed are determined.

[0054] In some embodiments, if the number of DRO reference orbits to be deployed is P, and the total number of satellites to be deployed is N, then P can be a factor of N. That is, N can be divided by P.

[0055] For example, if the total number of satellites to be deployed is 16, since the factors of 16 include 1, 2, 4, 8, and 16, any one of these values ​​can be selected as the number of DRO reference orbits to be deployed. For instance, if 4 is selected as the number of DRO reference orbits to be deployed, then 4 DRO reference orbits can be determined as the selected DRO reference orbits to be deployed.

[0056] In some embodiments, the initial phase of each DRO reference orbit to be deployed can be set based on mission requirements. (For example, (where i is a real number between [0°, 360°], i = 1, 2, ..., P. Then, the initial phase can be obtained as follows: The initial orbital state and orbital period of the DRO reference orbit.

[0057] S102: For a target satellite to be deployed in the target DRO reference orbit, determine the initial orbit state of the target satellite based on the orbit state corresponding to the target phase.

[0058] Among them, the target satellite is the satellite of the target phase to be deployed in the target DRO reference orbit.

[0059] In some embodiments, the number of satellites to be deployed on each DRO reference orbit can be determined based on the total number of satellites to be deployed and the number of DRO reference orbits to be deployed. Furthermore, the initial phase of the satellites deployed on each DRO reference orbit can be determined based on the number of satellites deployed on each DRO reference orbit.

[0060] In some embodiments, if the number of satellites deployed on each DRO reference orbit is Q (Q is an integer), the number of DRO reference orbits to be deployed is P, and the total number of satellites to be deployed is N, then Q = N / P.

[0061] For example, if the total number of satellites to be deployed, N, is 16, and the number of DRO reference orbits to be deployed, P, is 4, then the number of satellites to be deployed on each DRO reference orbit, Q, is determined to be 4. That is, 4 satellites need to be deployed on each DRO reference orbit.

[0062] In some embodiments, the empirical orbital state corresponding to the target phase can be determined based on the orbital state corresponding to the target phase in the plane DRO under the three-body model. The empirical orbital state corresponding to the target phase is obtained by fixing the z-axis component of the orbital state corresponding to the target phase to the maximum value region corresponding to the orbital period of the target DRO reference orbit. The direction of the z-axis is the same as the angular momentum direction of the lunar orbital plane in the four-body model. The maximum value region corresponding to the orbital period of the target DRO reference orbit is a preset region, which can be set by those skilled in the art based on actual scenarios and historical experience.

[0063] Subsequently, based on the differential evolution algorithm, the empirical orbit state corresponding to the target phase can be optimized using the empirical orbit state as the variable and the difference between the orbit period of the target DRO reference orbit and the target orbit period as the optimization objective. Based on the optimization results of the empirical orbit state corresponding to the target phase, the initial orbit state of the target satellite can be determined.

[0064] In some embodiments, when optimizing the empirical orbital state corresponding to the target phase based on the differential evolution algorithm, the orbital stability of the target DRO reference orbit can be controlled to be less than a first empirical threshold.

[0065] It should be noted that those skilled in the art can set the target orbital period and the first empirical threshold based on actual scenarios and needs, and the embodiments of this application are not limited thereto.

[0066] In some embodiments, the initial phase of each satellite deployed in each DRO reference orbit can be determined based on the initial phase of each DRO reference orbit to be deployed. For example, the initial phase of the i-th DRO reference orbit can be used as the basis for determining the initial phase of each satellite deployed in each DRO reference orbit. Determine the initial phase of the j-th satellite in the i-th DRO reference orbit. And j = 1, 2, ..., N / P.

[0067] In some embodiments, the initial orbital state of the target DRO reference orbit can be determined based on the optimization results of the empirical orbital state corresponding to the target phase. Then, the initial orbital state of the target satellite can be determined based on the initial orbital state of the target DRO reference orbit and the target phase.

[0068] For example, the target phase θ on the target DRO reference orbit ij The corresponding orbital state is determined to be with an initial phase of θ. ij The initial orbital state of the target satellite.

[0069] S103: Determine the orbital period of the target satellite based on the orbital period of the target DRO reference orbit.

[0070] In some embodiments, the orbital period of the target DRO reference orbit can be determined as the orbital period of the target satellite. That is, the orbital period of the target DRO reference orbit is equal to the orbital period of the target satellite. Since the orbital period of the target satellite is the same as that of the target DRO reference orbit, the orbital periods of all satellites located in the same DRO reference orbit are also the same, allowing satellites in the same DRO reference orbit to fly stably and maintain a relatively stable geometric configuration.

[0071] S104: Based on the target satellite's orbital period and initial orbital state, obtain the target satellite's corresponding target orbital state.

[0072] In some embodiments, the initial orbital state of the target satellite can be optimized based on a differential evolution algorithm, using the initial orbital state of the target satellite as a variable and the difference between the orbital period of the target satellite and the target orbital period as the optimization objective, to obtain the target orbital state of the target satellite.

[0073] In some embodiments, when optimizing the initial orbital state of the target satellite based on the differential evolution algorithm, the orbital stability of the target DRO reference orbit can be controlled to be less than a second empirical threshold.

[0074] It should be noted that those skilled in the art can set a second experience threshold based on actual scenarios and needs. The second experience threshold may be the same as or different from the first experience threshold, and the embodiments of this application do not impose any restrictions.

[0075] S105: A lunar global positioning constellation constructed based on the target orbital state of each satellite in a four-body model.

[0076] In some embodiments, Q satellites can be uniformly deployed on each DRO reference orbit; that is, Q satellites can be deployed on each DRO reference orbit using an equal phase difference deployment method, and the orbital state corresponding to each satellite is its corresponding target orbital state. Based on the satellites with corresponding target orbital states and uniformly distributed on each DRO reference orbit, a lunar global positioning constellation under the four-body model can be constructed.

[0077] Because the satellites are evenly distributed on the same DRO reference orbit, each satellite can maintain stable flight, thus maintaining a relatively stable geometric configuration.

[0078] The lunar global positioning constellation constructed by this invention saves on the total cost of constellation construction to a certain extent compared with the currently constructed near-lunar constellations.

[0079] On the one hand, the lunar global positioning constellation constructed by this invention can achieve pulse maneuvers without configuration maintenance for several years. Theoretically, the lunar global positioning constellation constructed by this invention can operate stably for at least 3 years and meet more than 98% lunar surface coverage. Therefore, the lunar global positioning constellation constructed by this invention can save on the cost of pulse fuel used for orbit maintenance to a certain extent.

[0080] On the other hand, the DRO included in the lunar global positioning constellation constructed by this invention can achieve autonomous orbit determination of satellites. That is, each satellite located on the DRO can determine its own orbital position through inter-satellite measurements, and can achieve autonomous orbit determination without the assistance of lunar surface base stations.

[0081] In some embodiments, see Figure 2 The configuration of the lunar global positioning constellation under the four-body model constructed in this invention can be represented as: N / P / θ0 / Z / T. Where N is the total number of satellites to be deployed, and P is the number of DRO reference orbits to be deployed. Z = {Z1, Z2, ..., Z} i}, T = {T1, T2, ..., T} i}, i = 1, 2, ..., P. Z represents the initial phase of the i-th DRO reference orbit. i T represents the initial z-axis component of the i-th DRO reference orbit. i This represents the orbital period of the i-th DRO reference orbit.

[0082] This configuration characterization (N / P / θ0 / Z / T) is applicable to any scale requirement of the number of satellites to be deployed, and can effectively solve the configuration design problem of building a lunar global positioning constellation with high lunar surface coverage under the four-body model based on the DRO reference orbit, which can operate stably for several years.

[0083] In some solutions, multiple embodiments of this application can be combined, and the combined solution can be implemented. Optionally, some operations in the processes of each method embodiment may be combined, and / or the order of some operations may be changed. Furthermore, the execution order between the steps of each process is merely exemplary and does not constitute a limitation on the execution order between steps; other execution orders are also possible. It is not intended to indicate that the execution order is the only possible order in which these operations can be performed. Those skilled in the art will conceive of various ways to reorder the operations described herein. In addition, it should be noted that the process details involved in one embodiment of this document are similarly applicable to other embodiments, or different embodiments may be combined.

[0084] Furthermore, some steps in the method embodiments can be equivalently replaced with other possible steps. Alternatively, some steps in the method embodiments may be optional and can be deleted in certain use cases. Or, other possible steps may be added to the method embodiments.

[0085] Furthermore, the various method embodiments can be implemented individually or in combination.

[0086] In the several embodiments provided in this application, it should be understood that the disclosed methods can be implemented in other ways.

[0087] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for designing a lunar global positioning constellation based on the Earth-Moon space DRO reference orbit, characterized in that, include: Based on the initial phase of any one of the DRO reference orbits to be deployed, determine the initial orbit state and orbit period of that DRO reference orbit. For any satellite to be deployed in any DRO reference orbit with an initial phase of the target phase, the initial orbit state of the satellite is determined based on the orbit state corresponding to the target phase. The orbital period of any satellite is determined based on the orbital period of any DRO reference orbit. Based on the orbital period and initial orbital state of any satellite, the target orbital state corresponding to any satellite is obtained; A lunar global positioning constellation is constructed based on the target orbit status of each satellite and the four-body model. Determining the initial orbital state and orbital period of any of the DRO reference orbits includes: Based on the orbital state corresponding to the target phase in the DRO plane under the three-body model, the empirical orbital state corresponding to the target phase is determined; the empirical orbital state corresponding to the target phase is obtained by fixing the z-axis component of the orbital state corresponding to the target phase to the maximum value region corresponding to the orbital period of any DRO reference orbit; the maximum value region is a preset region; the direction of the z-axis is the same as the angular momentum direction of the lunar orbital plane in the four-body model; Based on the differential evolution algorithm, the empirical orbital state corresponding to the target phase is used as a variable, and the difference between the orbital period of any DRO reference orbit and the target orbital period is used as the optimization objective to optimize the empirical orbital state corresponding to the target phase. Based on the optimization results of the empirical orbit state corresponding to the target phase, the initial orbit state of any DRO reference orbit is determined.

2. The method according to claim 1, characterized in that, Before determining the initial orbital state and orbital period of any DRO reference orbit, the method further includes: Based on the total number of satellites to be deployed, determine the number of DRO reference orbits to be deployed; The number of DRO reference orbits to be deployed is used to determine the DRO reference orbits to be deployed.

3. The method according to claim 2, characterized in that, The number of DRO reference orbits to be deployed is P, and the total number of satellites to be deployed is N, where P is a factor of N.

4. The method according to claim 3, characterized in that, Before determining the initial orbital state of any satellite based on the orbital state corresponding to the target phase, the method further includes: Based on the total number of satellites to be deployed and the number of DRO reference orbits to be deployed, determine the number of satellites to be deployed on each of the DRO reference orbits; The initial phase of the satellites deployed in each of the DRO reference orbits is determined based on the number of satellites deployed in each of the DRO reference orbits.

5. The method according to claim 4, characterized in that, The number of satellites deployed on each of the aforementioned DRO reference orbits is Q, where Q = N / P.

6. The method according to claim 1, characterized in that, Determining the orbital period of any satellite based on the orbital period of any DRO reference orbit includes: The orbital period of any DRO reference orbit is determined as the orbital period of any satellite.

7. The method according to claim 6, characterized in that, Determining the initial orbital state of any satellite based on the orbital state corresponding to the target phase includes: The initial orbital state of any satellite is determined based on the initial orbital state of any DRO reference orbit and the target phase.

8. The method according to claim 7, characterized in that, The process of obtaining the target orbit state corresponding to any satellite based on the orbital period and initial orbital state of any satellite includes: Based on the differential evolution algorithm, the initial orbital state of any satellite is used as a variable, and the difference between the orbital period of any satellite and the target orbital period is used as the optimization objective to optimize the initial orbital state of any satellite and obtain the target orbital state of any satellite.

9. The method according to claim 8, characterized in that, The lunar global positioning constellation built on the four-body model also includes: Q satellites are evenly deployed on each of the aforementioned DRO reference orbits.

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