EP-4738725-A1 - CONTROLLING INTER-SATELLITE COMMUNICATION LINKS IN A CONSTELLATION OF SATELLITES, AND TOPOLOGIES RESULTING THEREFROM

EP4738725A1EP 4738725 A1EP4738725 A1EP 4738725A1EP-4738725-A1

Abstract

Methods and systems are disclosed for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth. The constellation comprises n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m , n ≥ 3, and m ≥ 3. The method comprises outputting parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, while aiming at reducing latency in the transmission of data through the constellation. Computer programs, computer program products, and computer-readable storage medium are also disclosed.

Inventors

GROTZ, JOEL
Rao, Chirag
MODIANO, EYTAN

Assignees

SES Americom, Inc
Massachusetts Institute of Technology

Dates

Publication Date: 20260506
Application Date: 20251024

Claims (15)

Method, carried out by a processing device or a set of processing devices, for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth, the constellation comprising n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m , n ≥ 3, and m ≥ 3, the method comprising: outputting (s10) parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, in which, for each satellite of at least a subset of the satellites, an inter-satellite communication link for transmission of user data is established between the satellite, hereinafter referred to as "first satellite", and a second satellite of the constellation, wherein the first satellite is in a first orbital plane; the second satellite is in a second orbital plane adjacent to the first orbital plane; and the position of the second satellite in the second orbital plane is offset from a position of a satellite, hereinafter referred to as "third satellite", in the second orbital plane, the third satellite being closest to the first satellite among the satellites in the second orbital plane; it is refrained from establishing an inter-satellite communication link for transmission of user data between the first satellite and the third satellite; it is refrained from establishing an inter-satellite communication link for transmission of user data between the second satellite and any satellite of the first orbital plane other than the first satellite; and the above applies regardless of whether the first satellite is latitude-decreasing or latitude-increasing; and in which an identical inter-satellite communication link pattern as between the first orbital plane and the second orbital plane is applied between the second orbital plane and a third orbital plane adjacent to the second orbital plane, the third orbital plane being different from the first orbital plane.
Method of claim 1, wherein, in the inter-satellite communication link topology, for each first satellite, a further inter-satellite communication link for transmission of user data is established between the first satellite and a satellite, hereinafter referred to as "fourth satellite", that is adjacent to the first satellite in the first orbital plane.
Method of claim 2, wherein, in the inter-satellite communication link topology, for each first satellite, yet a further inter-satellite communication link for transmission of user data is established, if not existing already, between the first satellite and a satellite, hereinafter referred to as "fifth satellite", in the first orbital plane.
Method according to any one of the preceding claims, wherein, in the inter-satellite communication link topology, for each first satellite, the position of the second satellite in the second orbital plane is offset from the position of the third satellite by a number q of satellites between the second satellite and the third satellite, wherein q is an integer value depending on n, m , and a number of inter-satellite communication links per satellite, and q ≥ 0.
Method according to any one of the preceding claims, wherein the number of inter-satellite communication links per satellite is equal to 4.
Method of claim 5, wherein the inter-satellite communication link topology is defined by a jump set {[1 0] T , [k 1] T }, wherein k is an integer value with k = 2 m n − 1 ; operator … means rounding up to integer; and the jump set uses a notation wherein each pair [ a 1 a 2] T means, for each first satellite of the subset of the satellites, establishing an inter-satellite communication link from the first satellite to a satellite that is offset in intra-orbital-plane direction by a1 and in inter-orbital-plane direction by a2 .
Method of claim 5 or 6, wherein m = cn and c is a positive integer value.
Method according to any one of claims 1 to 4, wherein the number of inter-satellite communication links per satellite is equal to 3.
Method of claim 8, wherein m ≥ 6 and the inter-satellite communication link topology is defined by a jump set {[1 0] T ,[3 0] T ,[5 1] T }, wherein the subset of satellites comprises every other satellite in at least one orbital plane; and the jump set uses a notation wherein each pair [ a 1 a 2] T means, for each first satellite of the subset of the satellites, establishing an inter-satellite communication link from the first satellite to a satellite that is offset in intra-orbital-plane direction by a1 and in inter-orbital-plane direction by a2.
Method of claim 8 or 9, wherein m = 6n.
Method, carried out by a processing device or a set of processing devices, for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth, the constellation comprising n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m , n ≥ 3, and m ≥ 3, and wherein a cross-orbit row is here defined as a group of n satellites, each being in a different orbital plane and, if a satellite S 1 in an orbital plane O 1 and a satellite S 2 in an adjacent orbital plane O 2 are the closest to one another, satellite S 1 and satellite S 2 are in the same cross-orbit row, the method comprising: outputting (s10) parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, in which, for each satellite of at least a subset of the satellites, an inter-satellite communication link for transmission of user data is established between the satellite, hereinafter referred to as "first satellite", and a second satellite of the constellation, wherein the first satellite is in a first cross-orbit row; the second satellite is in a second cross-orbit row adjacent to the first cross-orbit row; and the position of the second satellite in the second cross-orbit row is offset from a position of a satellite, hereinafter referred to as "third satellite", in the second cross-orbit row, the third satellite being closest to the first satellite among the satellites in the second cross-orbit row; it is refrained from establishing an inter-satellite communication link for transmission of user data between the first satellite and the third satellite; and it is refrained from establishing an inter-satellite communication link for transmission of user data between the second satellite and any satellite of the first cross-orbit row other than the first satellite; and in which an identical inter-satellite communication link pattern as between the first cross-orbit row and the second cross-orbit row is applied between the second cross-orbit row and a third cross-orbit row adjacent to the second cross-orbit row, the third cross-orbit row being different from the first cross-orbit row.
System comprising a plurality of satellites forming an inter-satellite communication link topology established with a method according to any one of claims 1 to 11.
System for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth, the constellation comprising n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m , n ≥ 3, and m ≥ 3, the system comprising a processing device or set of processing devices, and the system being configured for: outputting (s10) parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, in which, for each satellite of at least a subset of the satellites, an inter-satellite communication link for transmission of user data is established between the satellite, hereinafter referred to as "first satellite", and a second satellite of the constellation, wherein the first satellite is in a first orbital plane; the second satellite is in a second orbital plane adjacent to the first orbital plane; and the position of the second satellite in the second orbital plane is offset from a position of a satellite, hereinafter referred to as "third satellite", in the second orbital plane, the third satellite being closest to the first satellite among the satellites in the second orbital plane; it is refrained from establishing an inter-satellite communication link for transmission of user data between the first satellite and the third satellite; it is refrained from establishing an inter-satellite communication link for transmission of user data between the second satellite and any satellite of the first orbital plane other than the first satellite; and the above applies regardless of whether the first satellite is latitude-decreasing or latitude-increasing; and in which an identical inter-satellite communication link pattern as between the first orbital plane and the second orbital plane is applied between the second orbital plane and a third orbital plane adjacent to the second orbital plane, the third orbital plane being different from the first orbital plane.
System for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth, the constellation comprising n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m , n ≥ 3, and m ≥ 3, and wherein a cross-orbit row is here defined as a group of n satellites, each being in a different orbital plane and, if a satellite S 1 in an orbital plane O 1 and a satellite S 2 in an adjacent orbital plane O 2 are the closest to one another, satellite S 1 and satellite S 2 are in the same cross-orbit row, the system comprising a processing device or set of processing devices, and the system being configured for: outputting (s10) parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, in which, for each satellite of at least a subset of the satellites, an inter-satellite communication link for transmission of user data is established between the satellite, hereinafter referred to as "first satellite", and a second satellite of the constellation, wherein the first satellite is in a first cross-orbit row; the second satellite is in a second cross-orbit row adjacent to the first cross-orbit row; and the position of the second satellite in the second cross-orbit row is offset from a position of a satellite, hereinafter referred to as "third satellite", in the second cross-orbit row, the third satellite being closest to the first satellite among the satellites in the second cross-orbit row; it is refrained from establishing an inter-satellite communication link for transmission of user data between the first satellite and the third satellite; and it is refrained from establishing an inter-satellite communication link for transmission of user data between the second satellite and any satellite of the first cross-orbit row other than the first satellite; and in which an identical inter-satellite communication link pattern as between the first cross-orbit row and the second cross-orbit row is applied between the second cross-orbit row and a third cross-orbit row adjacent to the second cross-orbit row, the third cross-orbit row being different from the first cross-orbit row.
Computer program or set of computer programs comprising computer-readable instructions configured, when executed on a computer or set of computers, to cause the computer or set of computers to carry out the method according to any one of claims 1 to 11.

Description

[Field of technology] The invention relates to the field of controlling a constellation of satellites orbiting the Earth and, in particular, to controlling inter-satellite communication links in such a satellite constellation. The invention may be used to, though not limited to, assist in providing connectivity, such as for example Internet connectivity, between gateways and/or terminals on or near the Earth's surface. [Background] A constellation of satellites orbiting the Earth, such as low Earth orbit (LEO) satellites, may be used for providing connectivity, such as for example Internet connectivity, to gateways and/or terminals on or near the Earth's surface. This may notably require inter-satellite links (ISL) for satellite-to-satellite communication for transmission of user data through the constellation of satellites. These ISLs may also be called "inter-satellite communication links" and may for example comprise free-space optical ISLs. The terminals may for example be mobile terminals. In view of the above, there is a constant need for improved solutions to assist in efficiently operating and controlling such satellite networks. [Summary] The present invention aims at addressing, at least partially, the above-mentioned need. The invention includes methods, systems, computer programs, computer program products, and computer-readable storage mediums as defined in the independent claims. Particular embodiments are defined in the dependent claims. In one embodiment, a method is carried out by a processing device or a set of processing devices, for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth. The constellation comprises n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m, n ≥ 3, and m ≥ 3. The method comprises: outputting parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, in which, for each satellite of at least a subset of the satellites, (i) an inter-satellite communication link for transmission of user data is established between the satellite, hereinafter referred to as "first satellite", and a second satellite of the constellation, wherein (a) the first satellite is in a first orbital plane; (b) the second satellite is in a second orbital plane adjacent to the first orbital plane; and (c) the position of the second satellite in the second orbital plane is offset from a position of a satellite, hereinafter referred to as "third satellite", in the second orbital plane, the third satellite being closest to the first satellite among the satellites in the second orbital plane; (ii) it is refrained from establishing an inter-satellite communication link for transmission of user data between the first satellite and the third satellite; (iii) it is refrained from establishing an inter-satellite communication link for transmission of user data between the second satellite and any satellite of the first orbital plane other than the first satellite; and (iv) the above (i.e., items (i), (ii), and (iii)) applies regardless of whether the first satellite is latitude-decreasing or latitude-increasing. Furthermore, in the inter-satellite communication link topology, an identical inter-satellite communication link pattern as between the first orbital plane and the second orbital plane is applied between the second orbital plane and a third orbital plane adjacent to the second orbital plane, wherein the third orbital plane is different from the first orbital plane. In another embodiment, a method is carried out by a processing device or a set of processing devices, for assisting in controlling inter-satellite communication links of a constellation of satellites orbiting the Earth. As in the first embodiment, the constellation comprises n orbital planes and m satellites per orbital plane, wherein n and m are positive integer values, n ≠ m, n ≥ 3, and m ≥ 3. A cross-orbit row is here defined as a group of n satellites, each being in a different orbital plane and, if a satellite S1 in an orbital plane O1 and a satellite S2 in an adjacent orbital plane O2 are the closest to one another, satellites S1 and S2 are in the same cross-orbit row. The method comprises: outputting parameters usable to control satellites of the constellation to establish an inter-satellite communication link topology for transmission of user data, in which, for each satellite of at least a subset of the satellites, (i) an inter-satellite communication link for transmission of user data is established between the satellite, hereinafter referred to as "first satellite", and a second satellite of the constellation, wherein (a) the first satellite is in a first cross-orbit row; (b) the second satellite is in a second cross-orbit row adjacent to the first cross-orbit row; and (c) the position of the second satellite in the second cro