Accurate division method for satellite constellation network time slices

Abstract

A satellite constellation network time slice accurate division method comprises the following steps: calculating inter-satellite link switching times and time slice lengths of satellite constellations at the same orbit height in a system period according to a single-layer constellation configuration to obtain same orbit layer network time slices; the method comprises the following steps: respectively calculating inter-satellite link switching times and time slice lengths of satellite constellations with different orbit heights in a system period by adopting a distance-first grouping strategy (DPGS); and calculating the link switching frequency and the time slice length between the satellite and the ground gateway station in the system period to obtain a satellite-ground network time slice. According to the method, the dynamic topological characteristics of the satellite network can be effectively evaluated, and the time slices of the satellite network can be quickly and accurately divided.

Description

Technical Field

[0001] The present invention relates to a technology in the field of satellite networks, specifically a method for accurately dividing time slices of a satellite constellation network. Background Art

[0002] A satellite constellation refers to a collection of multiple satellites that work together to complete a specific on-orbit mission. A satellite network consists of satellite nodes, ground nodes, and communication links between the nodes within the constellation. The existing calculation for dividing time slices of a satellite network includes the division of time slices for the inter-satellite network and the division of time slices for the satellite-ground network. The division of time slices for the inter-satellite network is generally calculated through orbit recursion and then indirectly calculates the division of network time slices in combination with the reachability of inter-satellite links. The division of time slices for the satellite-ground network calculates the division of network time slices by combining the satellite-ground coverage range and the reachability of satellite-ground links. Summary of the Invention

[0003] In view of the above deficiencies in the prior art, the present invention proposes a method for accurately dividing time slices of a satellite constellation network, which can effectively evaluate the dynamic topological characteristics of a satellite network and quickly and accurately divide the time slices of the satellite network.

[0004] The present invention is realized through the following technical solutions:

[0005] The present invention relates to a method for accurately dividing time slices of a satellite constellation network. According to the single-layer constellation configuration, the number of inter-satellite link switches and the time slice length of the satellite constellation at the same orbital altitude within the system period are calculated to obtain the network time slices of the same orbital layer. The distance-priority grouping strategy (DPGS) is used to calculate the number of inter-satellite link switches and the time slice length of the satellite constellations at different orbital altitudes within the system period respectively to obtain the network time slices of different orbital layers, and the number of link switches and the time slice length between satellites and ground gateway stations within the system period are calculated to obtain the satellite-ground network time slices. Technical Effects

[0006] Compared with the prior art, the calculation result of the time slice division of the present invention has an accurate analytical solution, so the actual calculation amount generated is very small, which can be directly processed by the on-board computer, and can greatly improve the real-time performance of on-board topology calculation. Description of the Drawings

[0007] Figure 1 is a flow chart of the present invention;

[0008] Figure 2 is a flow chart of the distance-priority grouping strategy;

[0009] Figure 3 is a schematic diagram of the grouping strategy for the satellite network of different orbital layers;

[0010] Figure 4 Schematic diagram of the packet strategy for the satellite-terrestrial satellite network;

[0011] Figure 5 Schematic diagram of the effect of the embodiment. Detailed implementation manners

[0012] As Figure 1 shown, this embodiment relates to a method for accurately dividing time slices of a satellite constellation network, including:

[0013] Step 1: Determine the single-layer constellation, that is, determine whether the configuration of multiple circular orbit satellites with the same orbital inclination and orbital height is the walker-δ configuration or the Polar configuration: When the inclination of each orbital plane in the constellation configuration is 90° or approximately 90°, it is the Polar configuration, otherwise it is the walker-δ configuration.

[0014] Step 2: Calculate the time slice division of the satellite network in the same orbital layer, specifically including:

[0015] Step 2.1: Calculate the time difference T between any two consecutive moments when a satellite node in the satellite network in the same orbital layer enters or leaves the polar region and the number n of times a satellite enters or leaves the polar region within the system period T according to the orbital inclination α, the polar region boundary latitude β, the number M of satellites on each orbit, c and the number n of times a satellite enters or leaves the polar region c , specifically including:

[0016] A) For the Polar constellation configuration: When α ≤ β, n c = 0, otherwise when M is even, T c = T / M, n c = M, when M is odd, T c = T / 2m, n c = 2M.

[0017] B) For the Walker-δ constellation configuration: When α ≤ β, n c = 0, otherwise when k = N / F is even, T c = T / kM, n c = kM, when M is odd, T c = T / 2kM, n c = 2kM; when k is non-integer and γ = mNM / F is even, T c = T Δω / m, n c = γ, T Δω = FT / (NM), when M is odd, T c = T Δω / 2m, n c= 2γ, N is the number of orbital planes, F is the phase factor of the constellation, where: mod(·) is the modulo operator, T Δω = FT / (NM).

[0018] Step 2.2: According to the link closure duration T caused by the satellite link in the adjacent orbital plane entering the polar region d and the time difference T between any two consecutive moments of entering or leaving the polar region in the satellite node set of the satellite network in the same orbital layer c ratio Calculate the upper and lower limits of the time slice length The time slice length and the number of time slices n, specifically: when q is an integer, the length of the current time slice is equal to the time interval T between any two consecutive successive entries or exits from the polar region boundary in the satellite node set, that is c equal, that is The number of time slices and the number of times n that the satellite enters or leaves the polar region c equal, that is n = n c ; otherwise n = 2n c , where: T m = mod(T d , T c ), T d = (π - 2ω β + Δω) / v, v is the average angular velocity of the satellite, that is 2π / T, Δω = 2πF / (NM).

[0019] Step 3: Adopt the distance - priority grouping strategy (DPGS) to calculate the number of inter - satellite link switches and the time slice length of the satellite constellation at different orbital altitudes within the system period to obtain the inter - orbital layer network time slice.

[0020] As Figure 2 shown, the distance - priority grouping strategy in Step 3 means: a hybrid constellation configuration composed of the LEO orbit, that is, the lower - layer satellite constellation and the MEO orbit, that is, the upper - layer satellite constellation. Each orbital plane adopts the Walker constellation configuration, where: all LEO satellites within the beam coverage of any MEO satellite are divided into a group, and the satellites within the group are member stars, and this MEO satellite is the leading star.

[0021] Preferably, when the member stars within any group change, it is considered that the network topology has changed, that is, the grouping of the management member stars of the MEO satellites within each topological time slice where: the set of MEO satellites and j = 1, …, M.

[0022] Preferably, when any LEO satellite is covered by multiple MEO satellites, the LEO satellite is divided into the group of the leading satellite with the shortest inter-satellite distance. Specifically: according to the set of all MEO satellites covering LEO satellite x In accordance with the principle of selecting the leading satellite closest to x in where: the set of LEO satellites within the coverage range of a certain MEO satellite is the number of satellites in

[0023] For example Figure 3 as shown, M1 ′ , M2 ′ and L ′ 1 are the sub-satellite points of MEO satellite M1, M2 and LEO satellite L1 respectively, and O is the center of the earth. According to the geometric relationship, it can be obtained that: the semi-central angle of the coverage range of the MEO satellite for the LEO satellite where: ε min is the minimum observation elevation angle of the LEO satellite,

[0024] To make the MEO satellite M1 completely cover the LEO satellite L1, the included angle between M1O and L1O That is: When the condition |M1 ′ L ′ 1| < |M2 ′ L ′ 1|, that is, |M1L1| < |M2L1|, M1 is the grouping leader of L1, otherwise it is M2.

[0025] The above-mentioned cross-orbit layer network time slice is calculated as follows: When the period of the LEO satellite is T l , and the period of the MEO satellite is T m , then the length T lm of the cross-orbit layer satellite network topology time slice division is the least common multiple of T l and T m . Within the length T lm of the topology time slice division, there are p topology time slices. Then within the time slices {[t i , t i+1 |i = 1, 2,..., p}, the grouping state is fixed and the network topology of the cross-orbit layer within the time slice remains unchanged.

[0026] Step 4: Calculate the number of link switches and the time slice length between satellites and ground gateway stations within the system cycle using the Distance-Priority Grouping Strategy (DPGS) to obtain the satellite-ground network time slice.

[0027] As Figure 4 shown, the distance-priority grouping strategy in Step 4 means that the lower-layer network nodes are ground terminal nodes or signal gateway stations, and the upper-layer network nodes are satellites. Among them: the semi-geocentric angle L ′ 1, L ′ 2 are the sub-satellite points of LEO satellites L1 and L2 respectively, G is the ground gateway station, O is the geocenter, and ε min is the minimum observation elevation angle of the gateway station to the satellite, R e , H l are the radius of the earth and the orbital altitude of the LEO satellite respectively; the angle between L1O and GO makes the LEO satellite L1 completely cover the gateway station G.

[0028] The length of the satellite-ground satellite network topology time slice is calculated as follows: Assume the period of the LEO satellite is T l , then the length T le of the satellite-ground satellite network topology time slice division is the least common multiple of T l and the earth's rotation period. Within the length T le of the topology time slice division, assume there are p topology time slices, then within the time slices {[t i , t i+1 |i = 1, 2, …, p}, the grouping state is fixed and the satellite-ground network topology within the time slice remains unchanged.

[0029] After specific simulation calculations, based on the time slice division of the first layer of the US Starlink satellite network, the polar region boundary β and the phase factor F, the basic constellation parameters shown in Table 1 are simulated. Through the calculation method of the satellite network topology time slice division in the same orbit layer of the present invention, the experimental results are as shown in Table 2 and Figure 5 shown.

[0030] Table 1 Basic constellation parameters in the simulation scenario of the multi-orbit layer satellite network

[0031] Table 2 Simulation results of the multi-orbit layer satellite network topology time slice division calculation

[0032] Based on the publicly available distribution of ground gateways and the Starlink and OneWeb constellation data, the basic constellation parameters shown in Table 3 are simulated. Through the calculation method of time slice division for the satellite network topology in the same orbital layer of the present invention, the experimental results are shown in Table 4.

[0033] Table 3 Basic Constellation Parameters in the Satellite-Ground Network Simulation Scenario

[0034] Table 4 Calculation Simulation Results of Time Slice Division for the Satellite-Ground Network Topology

[0035] Compared with the prior art, the present invention can calculate accurate analytical solutions by using the satellite network topology characteristics in the same orbital layer, the satellite network topology characteristics in different orbital layers, and the satellite-ground network topology characteristics, greatly improving the accuracy and computational overhead of topology calculation.

[0036] The above specific embodiments can be locally adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present invention. The protection scope of the present invention is subject to the claims and is not limited by the above specific embodiments, and all implementation solutions within its scope are subject to the present invention.

Claims

1. A method for accurately dividing time slices in a satellite constellation network, characterized in that, According to the single-layer constellation configuration, the number of inter-satellite link switches and the time slice length of the satellite constellation at the same orbital altitude within the system period are calculated to obtain the time slice of the same orbital layer network. The distance-priority grouping strategy (DPGS) is used to calculate the number of inter-satellite link switches and the time slice length of the satellite constellations at different orbital altitudes within the system period to obtain the time slice of the different orbital layer network. The number of link switches and the time slice length between the satellite and the ground gateway station within the system period are calculated to obtain the time slice of the satellite-ground network.

2. The method for accurately dividing time slices of a satellite constellation network according to claim 1, wherein The single-layer constellation configuration is determined by judging whether the configuration of multiple circular orbit satellites with the same orbital inclination and orbital altitude is a Walker-δ configuration or a Polar configuration: When the inclination of each orbital plane in the constellation configuration is 90° or approximately 90°, it is a Polar configuration; otherwise, it is a Walker-δ configuration.

3. The method for accurately dividing time slices of a satellite constellation network according to claim 1, characterized in that, The time slice of the same orbital layer network is calculated through the following method: Step 2.1: Calculate the time difference T between any two consecutive moments of a satellite entering or leaving the polar region in the satellite node set of the same orbital layer satellite network according to the orbital inclination angle α, the polar region boundary latitude β, the number of satellites M on each orbit, and within the system period T c and the number n of times a satellite enters or leaves the polar region c ; Step 2.2: According to the link closure duration T of the satellite link in the adjacent orbital plane due to entering the polar region d And the time difference T between any two consecutive moments of entering or leaving the polar region in the set of satellite nodes in the satellite network of the same orbital layer c Ratio Calculate the upper and lower limits of the time slice length The time slice length and the number of time slices n. Specifically: when q is an integer, the length of the current time slice is equal to the time interval T between any two consecutive successive entries or exits from the polar region boundary in the set of satellite nodes, that is c Equal, that is The number of time slices is equal to the number of times n that the satellite enters or leaves the polar region c Equal, that is n = n c Otherwise n = 2n c , where: T m = mod(T d , T c ), T d =(π - 2ω β +Δω) / v, v is the average angular velocity of the satellite, that is 2π / T, Δω = 2πF / (NM).

4. The method for accurately dividing time slices of a satellite constellation network according to claim 3, characterized in that The time difference T between two consecutive moments of entering or leaving the polar region c and the number n of times the satellite enters or leaves the polar region c , including: A) For the Polar constellation configuration: When α ≤ β, n c = 0, otherwise when M is even, T c = T / M, n c = M, when M is odd, T c = T / 2M, n c = 2M; B) For the Walker-δ constellation configuration: When α ≤ β, n c = 0, otherwise when k = N / F is even, T c = T / kM, n c = kM, when M is odd, T c = T / 2kM, n c = 2kM; when k is non-integer and γ = mNM / F is even, T c = T Δω / m, n c = γ, T Δω = FT / (NM), when M is odd, T c = T Δω / 2m, n c = 2γ, where N is the number of orbital planes, F is the phase factor of the constellation, where: mod(·) is the modulo operator, T Δω = FT / (NM).

5. The method for precisely dividing time slices of a satellite constellation network according to claim 1, wherein The time slice of the different orbital layer network is obtained by calculating the number of inter-satellite link switches and the time slice length of the satellite constellations at different orbital altitudes within the system period using the distance-priority grouping strategy (DPGS).

6. The method for accurately dividing time slices of a satellite constellation network according to claim 5, characterized in that, The distance-priority grouping strategy refers to: a hybrid constellation configuration composed of a LEO orbit, that is, the lower-layer satellite constellation, and a MEO orbit, that is, the upper-layer satellite constellation. Each orbital plane adopts a Walker constellation configuration, where: all LEO satellites within the beam coverage of any MEO satellite are divided into a group. The satellites within the group are member satellites, and this MEO satellite is the leading satellite.

7. The method for accurately dividing time slices of a satellite constellation network according to claim 6, characterized in that When the members of any group change, it is considered that the network topology has changed, that is, the management member star grouping of MEO satellites within each topology time slice Where: the set of MEO satellites And j = 1,..., M; When any LEO satellite is covered by multiple MEO satellites, the LEO satellite is divided into the group of the leading satellite with the shortest inter-satellite distance to it. Specifically: according to the set of all MEO satellites that cover LEO satellite x Select the leading satellite according to the principle of the closest distance to x in where: the set of LEO satellites within the coverage range of a certain MEO satellite is the number of satellites in ​ M1 ′ 、 M2 ′ and L ′ 1 are the sub - satellite points of MEO satellites M1, M2 and LEO satellite L1 respectively. O is the center of the earth. According to geometric relationships, the semi - geocentric angle of the coverage range of MEO satellites over LEO satellites can be obtained: where: ε min is the minimum observation elevation angle of the LEO satellite, R e , H l and H m are the radius of the earth, the orbital altitude of the LEO satellite and the orbital altitude of the MEO satellite respectively; To enable the MEO satellite M1 to completely cover the LEO satellite L1, the angle between M1O and L1O That is: When the condition |M1 ＇ L ′ 1| < |M2 ′ L ′ 1|, that is, |M1L1| < |M2L1|, M1 is the group leader of L1, otherwise it is M2; When the period of the LEO satellite is T l , and the period of the MEO satellite is T m , then the length T lm of the time slice division of the heterogeneous orbit layer satellite network topology is the least common multiple of T l and T m . Within the length T lm of the topology time slice division, there are p topology time slices. Then, within the time slices {[t i , t i+1 |i = 1, 2, …, p}, the packet state is fixed and the network topology of the heterogeneous orbit layer within the time slice remains unchanged.

8. The method for accurately dividing time slices of a satellite constellation network according to claim 1, characterized in that The time slice of the satellite-ground network is obtained by calculating the number of link switches and the time slice length between the satellite and the ground gateway station within the system period using the distance-priority grouping strategy (DPGS).

9. The method for accurately dividing time slices of a satellite constellation network according to claim 8, characterized in that, The described distance - priority grouping strategy means that the lower - layer network nodes are ground terminal nodes or signal gateway stations, and the upper - layer network nodes are satellites. Among them: the semi - geocentric angle of the coverage range of the LEO satellite gateway station L ′ 1. L ′ 2 are the sub - satellite points of LEO satellites L1 and L2 respectively, G is the ground gateway station, O is the earth's center, and ε min is the minimum observation elevation angle of the gateway station to the satellite, R e 、H l are the earth's radius and the LEO satellite orbital altitude respectively; the angle between L1O and GO makes the LEO satellite L1 completely cover the gateway station G.

10. The method for accurately dividing time slices of a satellite constellation network according to claim 9, characterized in that, When the period of the LEO satellite is T l , then the length of the time slice divided by the satellite-to-ground satellite network topology is T le T l and the least common multiple of the Earth's rotation period, in the length T of the topological time slice le In the time slice {[t i ,t i+1 ]|i=1,2,…,p}, the grouping state is fixed and the satellite-ground network topology remains unchanged within the time slice.

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