A method for establishing the topological structure of a multi-layer low-orbit giant constellation

Abstract

The present invention relates to a method for establishing a topological structure of a multi-layer low-orbit giant constellation, comprising: S100, for any two satellites in the multi-layer low-orbit giant constellation, which are respectively a first satellite and a second satellite, calculating whether the first satellite and the second satellite meet the topological relationship establishment rule; S200, when the first satellite and the second satellite meet the topological relationship establishment rule, establishing a topological relationship between the first satellite and the second satellite; S300, repeating steps S100 to S200 until a topological relationship is established between any two satellites in the multi-layer low-orbit giant constellation that meet the topological relationship establishment rule; wherein the topological relationship establishment rule is: when the orbital plane angle between the first orbital plane of the first satellite and the second orbital plane of the second satellite is less than a threshold angle, the topological relationship establishment rule is met. Thus, while ensuring the stability of the topological structure of the giant constellation, the scale and time of topological structure calculation are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of satellite topology, and in particular to a method for establishing a topological structure of a multi-layer low-orbit giant constellation. Background Art

[0002] With the advancement of technology and changes in market demand, compared with the early low-orbit constellations, the emerging giant constellation networks have the characteristics of large scale, low latency, and broadband, as shown below.

[0003] (1) Orbital hybridization. Most mega-constellations use multiple layers to form hybrid constellations, such as a combination of low orbit and ultra-low orbit, a combination of polar orbit and inclined orbit, etc. Hybrid constellations deploy a large number of inclined orbit satellites to cover low- and medium-latitude areas, and use polar orbit satellites to supplement high-latitude coverage to improve coverage performance.

[0004] (2) The constellation is huge. Traditional low-orbit constellation systems generally contain dozens of satellites, but giant constellation networks have expanded the number of satellites to tens of thousands to meet the needs of system capacity. Low-orbit ultra-dense constellations represented by Starlink and OneWeb set the constellation to a large scale of multiple orbits, multiple layers, and tens of thousands of satellites to enhance the system's transmission capacity and transmission latency.

[0005] (3) Intersatellite links. Microwave or laser links can be established between satellites and remain connected during movement, enabling data packets to be forwarded between satellites. For example, in the subsequent planning of Starlink, intersatellite links have been added, which can greatly increase the intersatellite communication rate and meet the needs of broadband services.

[0006] The above changes in constellation design will also bring new technical challenges and difficulties: inter-layer and inter-satellite movement, highly dynamic topological connections; large-scale inter-layer topological calculations; complex multi-layer satellite movement, and irregular inter-layer topological forms; changes in topological information lead to greater signaling overhead. Especially when the constellation has more than two or more layers, the node scale is huge, and the scale and time of inter-satellite topological calculations are difficult to control; the inter-satellite network topology changes highly dynamically, and the inter-satellite link routing is unstable; the space environment is complex. Summary of the invention

[0007] In view of this, the present invention aims to propose a method for establishing a topological structure of a multi-layer low-orbit giant constellation to solve the problem of complex spatial topology of the current highly dynamic multi-layer constellation.

[0008] An embodiment of the present invention provides a method for establishing a topological structure of a multi-layer low-orbit giant constellation, the method comprising:

[0009] S100, for any two satellites in the multi-layer low-orbit giant constellation, namely a first satellite and a second satellite, calculating whether the first satellite and the second satellite meet a topological relationship establishment rule;

[0010] S200: when the first satellite and the second satellite meet the topological relationship establishment rule, establish a topological relationship between the first satellite and the second satellite;

[0011] S300, repeating steps S100 to S200 until a topological relationship is established between any two satellites in the multi-layer LEO giant constellation that meet the topological relationship establishment rule;

[0012] The topological relationship establishment rule is:

[0013] The topological relationship establishment rule is met when the orbital plane angle between the first orbital plane of the first satellite and the second orbital plane of the second satellite is less than a threshold angle.

[0014] Preferably, the orbit where the first satellite is located is the first orbit, and the plane where the first orbit is located is the first orbital plane;

[0015] The orbit where the second satellite is located is the second orbit, and the plane where the second orbit is located is the second orbital plane.

[0016] Preferably, for the first satellite and the second satellite moving in the same direction, the threshold angle is an acute angle;

[0017] For the first satellite and the second satellite moving in opposite directions, the threshold angle is an obtuse angle.

[0018] Preferably, the projections of the first orbit and the second orbit on the earth have an intersection. In the projection direction to the earth, the first orbit has a first orbit intersection point at the intersection position, and the second orbit has a second orbit intersection point at the intersection position. When the angle between the movement direction of the first satellite at the first orbit intersection point and the movement direction of the second satellite at the second orbit intersection point is an acute angle, the first satellite and the second satellite have the same movement direction; when the angle between the movement direction of the first satellite at the first orbit intersection point and the movement direction of the second satellite at the second orbit intersection point is an obtuse angle, the first satellite and the second satellite have opposite movement directions.

[0019] Preferably, the first satellite and the second satellite are located in the same layer of the multi-layer low-orbit mega constellation.

[0020] Preferably, the first satellite and the second satellite are respectively located in different layers of the multi-layer low-orbit giant constellation.

[0021] Preferably, when the distance between the first satellite and the intersection point of the first orbit is within a predetermined range along the first orbit, and when the distance between the second satellite and the intersection point of the second orbit is within the predetermined range along the second orbit, an inter-satellite topology is established between the first satellite and the second satellite; when the distance between the first satellite and the intersection point of the first orbit is outside the predetermined range along the first orbit, and when the distance between the second satellite and the intersection point of the second orbit is outside the predetermined range along the second orbit, the inter-satellite topology between the first satellite and the second satellite is disconnected.

[0022] The embodiment of the present invention imposes conditional constraints on constellation link establishment of a multi-layer low-orbit giant constellation. A link can be established only when the angle between the orbital planes of two satellites meets a threshold angle, which greatly reduces the number of inter-satellite links. At the same time, for two satellites that can be linked, a link is only established near the orbital intersection, which greatly reduces the inter-satellite topology duration. Therefore, while ensuring the stability of the inter-satellite topology structure of a highly dynamic giant constellation, the scale and time of topology structure calculation are greatly reduced, and both stability and efficiency are taken into consideration. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of a flow chart of a method for establishing a topological structure of a multi-layer low-orbit giant constellation according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of the inter-layer topological relationship of a method for establishing a topological structure of a multi-layer low-orbit giant constellation according to an embodiment of the present invention;

[0026] Figure 3 A schematic top view of the intersatellite topological position of an embodiment of the present invention;

[0027] Figure 4 A schematic side view of the intersatellite topological position of an embodiment of the present invention;

[0028] Figure 5 Schematic diagram of the included angle of the inter-satellite orbital planes with the same moving direction according to an embodiment of the present invention;

[0029] Figure 6 Schematic diagram of the angle between intersatellite orbital planes with opposite motion directions according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0031] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0032] like Figure 1 As shown, an embodiment of the present invention provides a method for establishing a topological structure of a multi-layer low-orbit giant constellation, the method comprising:

[0033] S100: For any two satellites in the multi-layer low-orbit giant constellation, namely a first satellite and a second satellite, calculate whether the first satellite and the second satellite comply with a topological relationship establishment rule.

[0034] The topological relationship establishment rule is: when the orbital plane angle between the first orbital plane of the first satellite and the second orbital plane of the second satellite is less than a threshold angle, the topological relationship establishment rule is met. On the contrary, when the orbital plane angle is greater than the threshold angle, the topological relationship establishment rule is not met.

[0035] In this embodiment, the orbit of the first satellite is the first orbit, and the plane of the first orbit is the first orbital plane. The orbit of the second satellite is the second orbit, and the plane of the second orbit is the second orbital plane. For the first satellite and the second satellite with the same moving direction, the threshold angle is an acute angle (refer to Figure 5 ). For the first satellite and the second satellite moving in opposite directions, the threshold angle is an obtuse angle (refer to Figure 6 ). Among them, the relative motion direction between the two satellites is:

[0036] The projections of the first orbit and the second orbit on the earth have an intersection point. In the projection direction on the earth, the first orbit has a first orbit intersection point ( Figure 4 The track intersection point on the first track in the first track), the second track has a second track intersection point ( Figure 4When the angle between the moving direction of the first satellite at the intersection of the first orbit and the moving direction of the second satellite at the intersection of the second orbit is an acute angle, the first satellite and the second satellite move in the same direction. When the angle between the moving direction of the first satellite at the intersection of the first orbit and the moving direction of the second satellite at the intersection of the second orbit is an obtuse angle, the first satellite and the second satellite move in opposite directions.

[0037] S200: When the first satellite and the second satellite meet the topological relationship establishment rule, a topological relationship is established between the first satellite and the second satellite.

[0038] For two satellites that do not meet the topological relationship establishment rules, no topological relationship is established, and the process directly goes to step S300.

[0039] S300, repeating steps S100 to S200 until a topological relationship is established between any two satellites in the multi-layer LEO giant constellation that meet the topological relationship establishment rule.

[0040] It should be understood that in steps S100-S300, any two satellites in the constellation are respectively recorded as the first satellite and the second satellite, which is only used to distinguish two different satellites, and is not specifically limited to a certain one (or two) satellites in the constellation.

[0041] like Figure 2 As shown, the dotted line in the figure is the topological relationship that may exist between satellites in the current multi-layer giant constellation. Each satellite may have an inter-layer link. The multi-layer giant constellation is huge in scale, generally including hundreds, thousands, or even tens of thousands of satellites. When there are no constraints, the calculation volume is large and the calculation time is long. The solid line in the figure is a schematic diagram of the topological relationship between satellites in the inter-layer under the constraints of the present invention. It can be seen that the embodiment of the present invention can greatly reduce the scale of inter-satellite topology and the difficulty of calculation. This constraint can ensure that the link can be established, while reducing the number of highly dynamic inter-layer links and ensuring the stability of the link. Secondly, the constrained orbital plane motion angle of the satellite where the topological relationship can be established, the topology between different orbital planes between layers needs to have two orbital plane motion angle restrictions, and all satellite nodes with large orbital plane motion angles cannot establish inter-satellite topology. The reason is that the orbital plane motion angle is large and the inter-satellite topology connection time is short. It also takes time to build inter-satellite links. The short-term topology is not very meaningful, and the routing function is not obvious, but it will greatly increase the topology calculation overhead and the topology change signaling transmission overhead. Finally, the inter-satellite distance established by the topological relationship between the constraint layers and the inter-satellite topology will affect the quality, time and difficulty of link establishment.

[0042] like Figure 3-Figure 6As shown, the multi-layer low-orbit giant constellation of this embodiment can constrain satellites in the same layer, and can also be used for satellites in different layers. For layers with the same height, the position is near the intersection of the two orbits. When the satellite is about to reach the specified position, the topological relationship is established, and when the satellite exceeds the specified position, the topological relationship is disconnected. The distance between the satellites relative to the intersection point to establish or disconnect the topology can be a preset distance. For layers at different heights, the position for establishing the topological relationship is the intersection point of the two orbital planes, that is, the position where the two orbital planes are projected on the ground with the same coordinates. When the satellite is about to reach the specified position, the topological relationship is established, and when the satellite exceeds the specified position, the topological relationship is disconnected. Through the above-mentioned position design, at a certain moment, there are only two inter-layer links between the two orbital planes at most, that is, near the two intersection positions of the two orbital planes.

[0043] After the above-mentioned inter-layer topology constraint design and inter-layer topology position design, the relevant inter-satellite relationship is calculated. Compared with the case without the above-mentioned constraints and designs, it is only necessary to calculate the distance between the two orbital plane positions that meet the orbital angle constraint. On this basis, it is only necessary to calculate the distance between the satellites near the two intersection positions of the two orbital planes. According to the calculation results and the number of inter-layer links in the constellation, an inter-satellite topology table containing source satellites, target satellites, topology start time, and topology end time is designed. According to the actual situation, the topology table can be cut by time to form a topology table that meets the routing requirements, thereby completing the topology constraints of the entire multi-layer low-orbit giant constellation. It has the following advantages: ① Make full use of the motion characteristics of the constellation satellites to select a fixed inter-layer link building position ② Design topology link building constraints according to the topology stability requirements ③ Faced with massive satellite nodes and high dynamic environments, the topology calculation is fast and efficient. Thus, the stability and efficiency requirements of the multi-layer low-orbit giant constellation are met.

[0044] The above description is only a preferred 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for establishing a topological structure of a multi-layer low-orbit giant constellation, characterized in that: The method comprises: S100, for any two satellites in the multi-layer low-orbit giant constellation, namely a first satellite and a second satellite, calculating whether the first satellite and the second satellite meet a topological relationship establishment rule; S200: when the first satellite and the second satellite meet the topological relationship establishment rule, establish a topological relationship between the first satellite and the second satellite; S300, repeating steps S100 to S200 until a topological relationship is established between any two satellites in the multi-layer LEO giant constellation that meet the topological relationship establishment rule; The topological relationship establishment rule is: The topological relationship establishment rule is met when the orbital plane angle between the first orbital plane of the first satellite and the second orbital plane of the second satellite is less than a threshold angle; The orbit where the first satellite is located is the first orbit, and the plane where the first orbit is located is the first orbital plane; The orbit where the second satellite is located is the second orbit, and the plane where the second orbit is located is the second orbital plane; For the first satellite and the second satellite having the same moving direction, the threshold angle is an acute angle; For the first satellite and the second satellite moving in opposite directions, the threshold angle is an obtuse angle; The projections of the first orbit and the second orbit on the earth have an intersection point, in the projection direction on the earth, the first orbit has a first orbit intersection point at the intersection point, and the second orbit has a second orbit intersection point at the intersection point, when the angle between the movement direction of the first satellite at the first orbit intersection point and the movement direction of the second satellite at the second orbit intersection point is an acute angle, the first satellite and the second satellite have the same movement direction, and when the angle between the movement direction of the first satellite at the first orbit intersection point and the movement direction of the second satellite at the second orbit intersection point is an obtuse angle, the first satellite and the second satellite have opposite movement directions; When the distance between the first satellite and the intersection point of the first orbit is within a predetermined range along the first orbit, and when the distance between the second satellite and the intersection point of the second orbit is within the predetermined range along the second orbit, an intersatellite topology is established between the first satellite and the second satellite; When the distance between the first satellite and the intersection point of the first orbit is outside the predetermined range along the first orbit, and when the distance between the second satellite and the intersection point of the second orbit is outside the predetermined range along the second orbit, the intersatellite topology between the first satellite and the second satellite is disconnected.

2. The method for establishing a topological structure of a multi-layer low-orbit giant constellation according to claim 1, characterized in that: The first satellite and the second satellite are located in a same layer of the multi-layer low-orbit mega constellation.

3. The method for establishing a topological structure of a multi-layer low-orbit giant constellation according to claim 1, characterized in that: The first satellite and the second satellite are respectively located in different layers of the multi-layer low-orbit giant constellation.

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