A method for maintaining control of a mega constellation continuous coverage configuration

Abstract

This invention discloses a method for maintaining the continuous coverage configuration of a mega-constellation. The mega-constellation is composed of multiple sub-constellations operating in low-Earth orbit (LEO) circular orbits, with each sub-constellation having satellites of equal orbital semi-major axes. The continuous coverage constraints and atmospheric perturbation effects of the constellation are analytically decomposed into ascending node right ascension constraints, relative motion boundary constraints between coplanar adjacent satellites, and satellite orbital altitude constraints. Out-of-plane control potential functions, inter-satellite boundary control potential functions, and semi-major axis control potential functions are designed for these constraints, respectively. This constellation control method relies only on the motion states of the controlled satellites and coplanar adjacent satellites, without requiring global constellation information; therefore, it is a fully distributed and decentralized self-organizing control method.

Description

Technical Field

[0001] This invention relates to the field of satellite orbit control research technology, specifically to satellite relative orbit configuration maintenance technology, and more particularly to a method for maintaining the configuration of a giant constellation with continuous coverage. Background Technology

[0002] For mega-constellations operating in low Earth orbit (LEO), Earth coverage is a crucial performance indicator. Therefore, for these constellations, the relative positions of the satellites are more important than their absolute positions. Satellite orbits are subject to orbital perturbations and insertion errors, necessitating on-orbit maintenance to maintain their positions. Existing orbital maintenance methods are mainly divided into absolute configuration maintenance and relative configuration maintenance. For mega-constellations, absolute configuration maintenance leads to frequent on-orbit maneuvers, resulting in wasted control energy. Relative configuration maintenance relies on global information, which is inefficient due to the large number of satellites. Therefore, developing a relative motion maintenance method that meets the requirements of continuous satellite coverage missions, considers complex perturbation environments, and eliminates the need for frequent on-orbit maneuvers, is a significant problem that needs to be solved. Summary of the Invention

[0003] The purpose of this invention is to provide a control method for maintaining the continuous coverage configuration of a mega-constellation. Addressing the mission requirements of continuous constellation coverage, this method analyzes and establishes inter-satellite constraints for low-Earth orbit (LEO) mega-constellations and proposes a self-organizing control method for LEO mega-constellations based on artificial potential functions. This control method relies only on the motion states of the controlled satellites and their coplanar neighboring satellites, without requiring global constellation information; therefore, it is a fully distributed and decentralized self-organizing control method.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for maintaining and controlling the continuous coverage configuration of a giant constellation, characterized by:

[0005] The giant constellation is composed of multiple sub-constellations operating in low-Earth orbit circular orbits. The semi-major axis of the satellite orbits of each sub-constellation is equal. The continuous coverage constraint and atmospheric perturbation effect of the constellation are analytically decomposed into the right ascension constraint of the ascending node, the relative motion boundary constraint between coplanar adjacent satellites, and the satellite orbital altitude constraint. For the above constraints, out-of-plane control potential functions, inter-satellite boundary control potential functions, and semi-major axis control potential functions are designed respectively.

[0006] S1: The out-of-plane control potential function is mainly affected by the right ascension constraint of the ascending node. Since the right ascension control of the ascending node also affects the orbital inclination, out-of-plane control needs to both constrain the drift range of the right ascension of the ascending node and keep the orbital inclination unaffected by perturbations and control effects. The out-of-plane control potential function φ iΩ for

[0007] Among them, Ω * The right ascension of the ascending node under J2 perturbation.

[0008] S2: The inter-satellite boundary control potential function is mainly based on the influence of the inter-satellite relative motion boundary constraints between two coplanar adjacent stars, considering the minimum boundary constraint d of the two coplanar adjacent stars. min and maximum boundary constraint d max Design the inter-satellite boundary control potential function φ bound Written as

[0009]

[0010] For inter-satellite boundary control, the motion states of the controlled satellite and its coplanar adjacent satellites will influence each other. Therefore, for three coplanar adjacent satellites i-1, i, and i+1, the self-organizing control rules are defined as follows: When satellite i satisfies the inter-satellite boundary constraints with two adjacent satellites, or satisfies the inter-satellite boundary constraints with neither of its two adjacent satellites, satellite i does not perform inter-satellite boundary control; if satellite i satisfies the inter-satellite boundary constraints with one coplanar adjacent satellite but does not satisfy the inter-satellite boundary constraints with another coplanar adjacent satellite, then satellite i will perform inter-satellite boundary control.

[0011]

[0012] S3: The semi-major axis control potential function is executed only if the above-mentioned ascending node right ascension constraint and inter-satellite boundary constraint are satisfied. Atmospheric drag perturbations in the low-Earth orbit environment will affect the satellite's orbital altitude, and the satellite orbit must be raised in a timely manner to ensure the normal operation of the constellation. Semi-major axis control potential function φ a Written as

[0013]

[0014] The present invention provides a method for maintaining the continuous coverage configuration of a giant constellation, which has the following advantages compared with existing technologies: The method analytically decomposes the continuous coverage constraints and atmospheric perturbation effects of the constellation into ascending node right ascension constraints, relative motion boundary constraints between coplanar adjacent satellites, and satellite orbital altitude constraints. Out-of-plane control potential functions, inter-satellite boundary control potential functions, and semi-major axis control potential functions are designed for these constraints respectively. This constellation control method relies only on the motion states of the controlled satellites and the motion states of coplanar adjacent satellites, without requiring global constellation information; it is a completely distributed and decentralized self-organizing control method. Attached Figure Description

[0015] Figure 1 This is a flowchart of a method for maintaining the continuous coverage configuration of a giant constellation according to the present invention;

[0016] Figure 2 A schematic diagram of the coverage zone between adjacent orbital planes of a giant constellation;

[0017] Figure 3 This is a schematic diagram showing the inter-stellar positional relationship between two adjacent stars. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and by providing a detailed description of a preferred embodiment.

[0019] like Figure 1 As shown, a method for maintaining the continuous coverage configuration of a giant constellation in this embodiment includes the following steps:

[0020] S1. A mega-constellation is composed of multiple sub-constellations operating in low-Earth orbit circular orbits, with each sub-constellation having an equal semi-major axis of its satellite orbit; consider that a mega-constellation contains P orbital planes, with S satellites evenly distributed on each orbital plane. Figure 2 A schematic diagram of the coverage zone between adjacent orbital planes of a giant constellation. Figure 3 This diagram illustrates the inter-satellite positional relationship between two adjacent satellites. The satellites are simplified to point masses, and D and E are two coplanar adjacent satellites. The two circles centered on D and E represent the coverage area of ​​the satellites. From the diagram, it can be seen that the difference in ascending nodes δΩ between coplanar adjacent satellites is the allowable drift range of the ascending nodes, and the geocentric angle θ between coplanar adjacent satellites is the allowable drift range.

[0021] The drift range of adjacent satellites in the same orbital plane is mainly represented by δΩ, i.e., the difference in right ascension of the ascending node, and its constrained range is [δΩ]. min ,δΩ max Let Ω be the right ascension of the ascending node of the satellite's orbit. * Let the right ascension of the ascending node of the satellite under the J2 perturbation be given. For example... Figure 3 As shown, due to the influence of orbital insertion error and complex perturbations, the constraint range of the right ascension of the ascending node should satisfy...

[0022]

[0023]

[0024]

[0025]

[0026] Where, α max The geocentric angle of the coverage area of ​​a single satellite.

[0027] The out-of-plane control potential function is mainly affected by the right ascension constraint of the ascending node. Since the right ascension control of the ascending node also affects the orbital inclination, out-of-plane control needs to both constrain the drift range of the right ascension of the ascending node and keep the orbital inclination unaffected by perturbations and control effects. The out-of-plane control potential function φ iΩ for

[0028] Where, k iΩ Here, represents the control coefficient of the out-of-plane control potential function, and represents the satellite orbital inclination. * Design orbital inclinations for giant constellations.

[0029] S2, such as Figure 3 As shown, the maximum and minimum boundaries of the inter-satellite relative distance between coplanar adjacent satellites within one orbital period are respectively

[0030]

[0031]

[0032] Among them, [θ min ,θ max ] represents the offset range of the geocentric angle θ of coplanar adjacent satellites under the coverage constraint, and a is the semi-major axis of the satellite.

[0033] The inter-satellite boundary control potential function is mainly based on the influence of the inter-satellite relative motion boundary constraints between two coplanar adjacent stars, considering the minimum boundary constraints between two coplanar adjacent stars. and maximum boundary constraints Design the inter-satellite boundary control potential function φ bound Written as

[0034]

[0035] Where, k bound For the boundary control potential function coefficients, [d min ,d max [ ] represents the inter-satellite distance control variable; the purpose of potential function control is to control d. max and d min convergence to Within the specified range, thus satisfying the inter-satellite boundary constraints brought about by continuous coverage.

[0036] In the inter-satellite boundary control potential function, the motion states of the controlled satellite and its coplanar adjacent satellites influence each other. Therefore, for three coplanar adjacent satellites i-1, i, and i+1, the self-organizing control rule is defined as follows: When satellite i satisfies the inter-satellite boundary constraints with its two neighboring satellites, or satisfies neither of the inter-satellite boundary constraints with its two neighboring satellites, satellite i does not perform inter-satellite boundary control; if satellite i satisfies the inter-satellite boundary constraints with one coplanar adjacent satellite but does not satisfy the inter-satellite boundary constraints with another coplanar adjacent satellite, then satellite i will perform inter-satellite boundary control.

[0037]

[0038] Where, d i,i-1,min The minimum distance between adjacent satellites i-1 and i is given by d. Similarly, di,i-1,max d represents the maximum distance between adjacent satellites i-1 and i. i,i+1,min d represents the minimum distance between adjacent satellites i and i+1. i,i+1,max This represents the maximum distance between adjacent satellites i and i+1.

[0039] S3. The semi-major axis deviation of constellation satellites causes long-term perturbed drift between satellites, thus disrupting the constellation configuration. Therefore, during the constellation's operation in orbit, it is necessary to maintain zero semi-major axis deviation between satellites to form a stable and bounded relative motion relationship. On the other hand, in the low Earth orbit (LEO) environment, satellites are affected by atmospheric drag perturbations, and their orbital altitude decreases over time. It is essential to raise the orbital altitude of the large LEO constellation in a timely manner to ensure its normal operation. Therefore, semi-major axis control of constellation satellites is imperative. The semi-major axis control potential function is mainly used to ensure the satellite's orbital altitude and is executed if and only if the aforementioned ascending node right ascension constraint and inter-satellite boundary constraint are satisfied.

[0040] Semi-major axis control potential function φ a Written as

[0041]

[0042] Where, k a Here, is the control coefficient of the potential function, and 'a' is the actual semi-major axis of the satellite. * Design the semi-major axis of the orbit for giant constellations.

[0043] In summary, considering the continuous coverage constraint of a large low-Earth orbit constellation, the control potential function executed on a single satellite within the constellation is as follows:

[0044]

[0045] The giant constellation continuous coverage configuration maintenance control method described in this invention analytically decomposes the continuous coverage constraints and atmospheric perturbation effects of the constellation into ascending node right ascension constraints, relative motion boundary constraints between coplanar adjacent satellites, and satellite orbital altitude constraints. Out-of-plane control potential functions, inter-satellite boundary control potential functions, and semi-major axis control potential functions are designed for these constraints respectively. This constellation control method relies only on the motion states of the controlled satellites and coplanar adjacent satellites, without requiring global constellation information; therefore, it is a fully distributed and decentralized self-organizing control method.

Claims

1. A method for maintaining the continuous coverage configuration of a giant constellation, characterized in that: The giant constellation is composed of multiple sub-constellations operating in low-Earth orbit circular orbits, with each sub-constellation having a satellite orbit semi-major axis of equal length. The continuous coverage constraint and atmospheric perturbation effect of the constellation are analytically decomposed into the ascending node right ascension constraint, the relative motion boundary constraint between coplanar adjacent satellites, and the satellite orbital altitude constraint. Out-of-plane control potential function, inter-satellite boundary control potential function and semi-major axis control potential function are designed respectively. The out-of-plane control potential function φ iΩ for The drift range of adjacent satellites in the same orbital plane is represented by the difference in right ascension of the ascending node, δΩ, and its constraint range is [δΩ]. min ,δΩ max ], where Ω is the right ascension of the ascending node of the satellite's orbit. * Let k be the right ascension of the ascending node of the satellite under J2 perturbation. iΩ The control coefficients of the out-of-plane control potential function; i is the satellite orbital inclination angle, i * Design orbital inclinations for giant constellations; The inter-satellite boundary control potential function φ bound for Among them, the minimum boundary constraint of two coplanar adjacent stars and maximum boundary constraints k bound For the boundary control potential function coefficients, [d min ,d max [This is] the inter-satellite distance control variable; The semi-major axis control potential function φ a for Where, k a Here, is the control coefficient of the potential function, and 'a' is the actual semi-major axis of the satellite. * Design the semi-major axis of the orbit for giant constellations.

2. The method for maintaining and controlling the continuous coverage configuration of giant constellations as described in claim 1, characterized in that: The aforementioned right ascension constraint of the ascending node is affected by orbital insertion error and complex perturbations. The constraint range of the right ascension of the ascending node should satisfy... Where P is the number of orbital planes contained in the giant constellation, and S is the number of satellites evenly distributed on each orbital plane; α max The geocentric angle of the coverage area of ​​a single satellite.

3. The method for maintaining and controlling the continuous coverage configuration of giant constellations as described in claim 1, characterized in that: The inter-satellite boundary control potential function is described above. The motion states of the controlled satellite and its coplanar adjacent satellites influence each other. Therefore, for three coplanar adjacent satellites i-1, i, and i+1, the self-organizing control rules are defined as follows: When satellite i satisfies the inter-satellite boundary constraints with two adjacent satellites, or satisfies neither of the inter-satellite boundary constraints with either of the two adjacent satellites, satellite i does not perform inter-satellite boundary control. If satellite i satisfies the inter-satellite boundary constraints with one coplanar adjacent satellite but does not satisfy the inter-satellite boundary constraints with the other coplanar adjacent satellite, then satellite i will perform inter-satellite boundary control. Where, d i,i-1,min d represents the minimum distance between adjacent satellites i-1 and i. i,i-1,max d represents the maximum distance between adjacent satellites i-1 and i. i,i+1,min d represents the minimum distance between adjacent satellites i and i+1. i,i+1,max This represents the maximum distance between adjacent satellites i and i+1.

4. The method for maintaining and controlling the continuous coverage configuration of giant constellations as described in claim 1, characterized in that: The maximum and minimum boundaries of the inter-satellite relative distance between coplanar adjacent satellites within one orbital period are respectively Among them, [θ min ,θ max [ ] represents the offset range of the geocentric angle θ of coplanar adjacent satellites under coverage constraints.

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