Satellite internet time-varying routing method and system based on prediction topology

Abstract

The invention discloses a time-varying routing method and system for a satellite internet, and mainly solves the problems that an existing satellite network routing method is difficult to support satellite high-quality communication, the topology is frequently changed, and the information communication load between satellites is heavy. According to the scheme, the method comprises the following steps: initializing orbit parameters of satellite nodes and an inter-satellite link set; obtaining a link on-off timetable through simulation, and sending the link on-off timetable to a satellite node by a ground station; the satellite node generates a topology prediction message according to the link on-off time table, determines the sending time of the message according to the difference value between the link change moment and the sending time of the routing control message, and floods the message in the limited area; and after receiving the message, the satellite node analyzes the link information to calculate a virtual route, arranges a route updating sequence of the satellite node, replaces the route table with the virtual route table at the link change moment, and issues the route to the basic network layer. According to the method, the transmission load of the network can be effectively reduced, the probability of outdated routing and packet loss is reduced, the method can be used for establishing the satellite internet, and the communication quality between satellites is guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of communication technology, and in particular relates to a calculation method and system for satellite network time-varying routing, which can be used for establishing satellite Internet and ensuring the communication quality between satellites. Background Art

[0002] Satellite Internet is a new type of network that can provide broadband Internet access and other communication services to ground and air terminals. The routing algorithm of satellite Internet is an important part of satellite communication. Efficient routing calculation can reduce the load of satellite nodes and improve service quality.

[0003] The traditional link state-based routing method is a dynamic routing method that dynamically updates the network topology by sensing the state changes of each link in the network in real time. In this method, the satellite node periodically senses the link state and floods its information, that is, broadcasts the link state to all nodes in the network to ensure that each node can obtain the latest network topology information. Although this method can effectively respond to changes in network topology and adjust routing strategies in a timely manner, it also has some potential problems, especially the risk of packet loss during data packet transmission.

[0004] The domain-based link state flooding mechanism is a strategy to optimize the traditional link state routing method. It divides the network into multiple regions to limit the flooding range of link state information. When a node in the network detects the interruption or restoration of the link, only the nodes in the domain where the topology change occurs will update and propagate the link state. This mechanism effectively reduces the network load and avoids the heavy burden of flooding the entire network. However, this method still has a certain risk of packet loss during data transmission, and will cause a certain delay in large-scale networks, which will have an adverse effect on the real-time performance of the network.

[0005] The patent document with publication number CN118870460A discloses a satellite Internet distributed mobility management method and system. This method uses VIP and subVIP management mechanisms to hide the mobility of satellites. The old satellite synchronizes the connection management information and satellite routes of online users to the new satellite in real time, so that users can maintain the same IP address before and after satellite switching, effectively reducing the online delay of mobile users and the signaling overhead of satellite switching. However, this method does not consider the impact of natural factors such as solar eclipses on the satellite network topology. When the satellite node encounters the above factors during operation, it will cause outdated routes and packet loss in the satellite network, affecting the service quality of the satellite network.

[0006] The patent document with publication number CN1905512A discloses a monitoring and analysis system for the OSPF routing protocol of the Internet, which is composed of a management node and one or more monitoring nodes distributed in each AS in the monitored network. This method completes routing monitoring in a way that minimizes the impact on the network, and summarizes the routing change information in each area obtained by multiple monitoring nodes, expands the system monitoring range, and can support routing performance monitoring of large and complex multi-area networks. However, this method mainly focuses on the monitoring and analysis of the performance of Internet routing protocols, and does not completely solve the problems of service quality and excessive transmission load of satellite networks. Summary of the invention

[0007] The purpose of the present invention is to address the above-mentioned problems and propose a satellite Internet time-varying routing method and system based on predictive topology, so as to fully consider the time-varying and predictability of network topology in large-scale satellite Internet scenarios, improve the utilization rate of satellite resources, effectively reduce the delay caused by link changes and sudden factors, and improve the service quality of satellite Internet.

[0008] To achieve the above-mentioned purpose, the technical solution of the present invention includes: a time-varying routing method for satellite Internet, a time-varying routing system for satellite Internet, an electronic device and a readable medium, wherein:

[0009] 1. A time-varying routing method for satellite Internet, characterized in that it includes:

[0010] (1) Initialize the satellite nodes, initialize the topology prediction message to be sent sequence to be empty, initialize the message processing queue to be empty, and set the topology prediction message sending threshold to T threshold , initialize the orbit parameters of the satellite node, calculate the angular velocity ω, orbit period T, true anomaly θ of the satellite node t and spatial position (x t ,y t , z t );

[0011] (2) Initialize the inter-satellite link set of the satellite node. The ground station initializes the inter-satellite link set {(l i , cost i , S i , sj)}, satellite node angular velocity ω, orbital period T, true anomaly θ t and spatial position (x t ,y t , z t ), obtain the satellite link on-off schedule through the satellite toolkit STK simulation, and send the link on-off schedule to the satellite node;

[0012] (3) After receiving the link on / off schedule, the satellite node generates a topology prediction message, which includes the link change time, link change status, link cost value, link start node and destination node information;

[0013] (4) Obtain the sending time of the routing control message from the satellite's system clock, obtain the link change time from the topology prediction message, calculate the difference between the two to determine the sending time of the topology prediction message, and send it to the neighboring satellite node;

[0014] (5) After receiving the routing control message, the satellite node stores it in the message processing queue and floods the routing control message in the limited area;

[0015] (6) Take out the routing control message from the satellite node's message processing queue, parse the topology prediction message therein, arrange the order of satellite node routing table updates according to the link change time, calculate the virtual routing table entry before the link changes, use the virtual routing table entry to switch the satellite node's routing table entry at the link change time, and send the route.

[0016] Furthermore, in step (1), the orbital parameters of the satellite node are initialized, and the angular velocity ω, orbital period T, and true anomaly θ of the satellite node are calculated. t and spatial position (x t ,y t , z t ), which includes:

[0017] (1a) Initialize the satellite node orbit parameters {α, e, i, Ω, ω, v}, where α is the semi-major axis of the satellite node, e is the eccentricity of the satellite node, i is the orbit inclination of the satellite node, Ω is the right ascension of the ascending node of the satellite node, ω is the argument of perigee of the satellite node, and v is the mean anomaly of the satellite node;

[0018] (1b) Based on the radius of the Earth R and the orbital height of the satellite h s Calculate the semi-major axis of the satellite node r = R + h s ; Calculate the angular velocity of the satellite based on the semi-major axis r Calculate the orbital period based on the satellite's angular velocity ω Among them, G is the gravitational constant, M is the mass of the earth;

[0019] (1c) Calculate the true anomaly θ of the satellite at any time t and spatial position [x t ,y t , z t ].

[0020] Further, in (2), the inter-satellite link set of the satellite node is initialized, and the ground station is based on the inter-satellite link set {(l i , costi , S i , S j )}, the angular velocity ω of the satellite node, the orbital period T, the true anomaly θ t and spatial position (x t ,y t , z t ), and obtain the satellite link on-off schedule through satellite toolkit STK simulation, including:

[0021] (2a) Initialize the intersatellite link set of the satellite node, expressed as:

[0022] {(l i , cost i , S i , S j )},i,∈[0,n]

[0023] Among them, l i represents the i-th link in the satellite network, cost i represents the cost value of the i-th link, S i and S j represents the starting satellite node ID and the destination satellite node ID of the link, and n is the number of nodes in the satellite Internet;

[0024] (2b) The ground station sets the inter-satellite link set of the satellite node {(l i , cost i , S i , S j )} and the satellite node's angular velocity ω, orbital period T, true anomaly θ t and spatial position (x t ,y t , z t ) is used as the input data of the satellite toolkit STK, and after simulation, the link on-off schedule of the satellite node is output.

[0025] Further, the satellite node in (3) generates a topology prediction message after receiving the link on / off schedule, and its implementation includes:

[0026] (3a) Satellite nodes obtain data from the link on / off schedule

[0027] (3b) Determine whether the satellite node is equal to S i :

[0028] If the two are not equal, skip the data and continue to read the next data until the link on / off table traversal is completed;

[0029] If the two are equal, read the corresponding link information l i , link cost value costi , link state value state i and link change time Δt i , generate a topology prediction message. The topology prediction message structure is based on the network layer reachability information NLRI structure and adds a link change time attribute. This attribute is a 32-bit integer data type and is used to set the timer to calculate the virtual routing table of the satellite node.

[0030] Furthermore, the difference between the two is calculated in (4) to determine the time of sending the topology prediction message, and its implementation includes:

[0031] (4a) Based on the satellite node system clock value T c And the sending cycle of routing control message T Route Calculate the time t at which the routing control message is sent Route ;

[0032] (4b) Predict the link change time Δt in the message based on the topology i The time t when the routing control message is sent Route , calculate the difference ΔT between the two i :

[0033] (4c) The difference ΔT i The topology prediction message sending threshold T set by the satellite node threshold For comparison:

[0034] If ΔT i ≤T threshold , the satellite node immediately generates a routing control message and merges the topology prediction message, and sends it to the neighboring satellite node;

[0035] If ΔT i >T threshold , the topology prediction message is stored in the topology prediction message to be sent sequence, and at the time of sending the routing control message, all the topology prediction messages in the sequence are merged into the routing control message and sent to the neighboring satellite node.

[0036] Furthermore, the implementation of flooding the routing control message in a limited area in (5) includes:

[0037] (5a) According to the orbital position of the satellite node (x o ,y0) information calculation satellite node area ID:

[0038]

[0039] Among them, M o is the number of satellite Internet orbits, h is the number of horizontal orbital planes in the area, and l is the number of vertical orbital planes in the area;

[0040] (5b) The satellite node compares the AS number in the routing control message with the calculated area ID:

[0041] If the AS number = area ID, the routing control message is stored in the satellite node's message processing queue and the message is forwarded to the neighboring satellite node;

[0042] If the AS number ≠ area ID, stop forwarding the routing control message and discard the message.

[0043] Furthermore, the order of arranging the update of the routing table according to the time of link change in (6) is implemented as follows:

[0044] (6a) The satellite node obtains the routing control message from the message processing queue, parses the topology prediction message in the routing control message, and obtains the link information in the message. i , link change time Δt i , link cost value cost i , link state i , Link start node S i and link destination node S j ;

[0045] (6b) The satellite node determines the virtual route calculation start time ΔT i :

[0046] ΔT i =Δt i -T pre

[0047] Among them, T pre The maximum virtual route calculation time set for satellite nodes,

[0048] (6c) Satellite node at ΔT i Set a timer at every moment to perform virtual routing calculation, obtain the virtual routing table of the satellite node, and i The satellite node's routing table is always replaced with a virtual routing table that is sent to the satellite node's basic network layer.

[0049] 2. A time-varying routing system for satellite Internet, comprising:

[0050] A topology prediction message generation module is used for the satellite node to receive the link on / off schedule sent by the ground station, parse the link change data therein and generate a topology prediction message;

[0051] A topology prediction message sending module is used to calculate the difference between the topology prediction message link change time and the routing control message sending time, determine the message sending time, merge the topology prediction message into the routing control message and send it to the surrounding neighbor nodes;

[0052] The limited area flooding module is used to determine the sending range of the routing control message after the satellite node receives the routing control message, that is, to compare the AS number of the routing control message with the area ID to which the satellite node belongs. If the two are equal, the message will continue to be sent to the surrounding neighboring nodes, otherwise the message will be discarded;

[0053] Virtual routing calculation module, used by satellite nodes to parse topology prediction messages and set timers for virtual routing calculations, and read link change time Δt in topology prediction messages i , to determine the virtual routing calculation start time ΔT i , and set a timer at this moment to perform virtual routing calculation. i The satellite node's routing table is always replaced with a virtual routing table and sent to the satellite node's basic network layer.

[0054] 3. An electronic device comprising a processor, a memory, an input / output device, a communication interface, and a computer program stored in the memory and executable on the processor, wherein the processor implements the time-varying routing method of the satellite Internet when executing the program.

[0055] 4. A computer-readable storage medium, characterized in that the storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the above-mentioned time-varying routing method of satellite Internet.

[0056] Compared with the prior art, the present invention has the following advantages:

[0057] First, after receiving the link on-off time table 1, the satellite node in the present invention generates a topology prediction message, merges it into the routing control message, and sends it at the routing control message sending time. By limiting the message sending frequency, the network transmission load is effectively reduced.

[0058] Secondly, in the present invention, the topology prediction message and satellite network routing calculation are only performed within a limited area, which effectively reduces the network congestion and resource waste problems between satellite network nodes;.

[0059] Third, after receiving the topology prediction message, the satellite node in the present invention determines the virtual routing table update time according to the link change time, sets a timer to start the routing calculation at the start time of the virtual routing calculation, and switches the routing table to the virtual routing table at the link change time, which effectively reduces the probability of outdated routing and packet loss, and ensures the service quality of satellite Internet. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 The present invention provides a flow chart of a time-varying routing method for satellite Internet according to embodiment 1;

[0061] Figure 2 This is a topology prediction message structure diagram in Example 1 of the present invention;

[0062] Figure 3 is a schematic diagram of the region in Example 1 of the present invention;

[0063] Figure 4 This is a schematic diagram of node routing calculation in Embodiment 1 of the present invention;

[0064] Figure 5 The embodiment 2 of the present invention provides a block diagram of a time-varying routing system for satellite Internet;

[0065] Figure 6 It is a schematic diagram of the structure of an electronic device provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0066] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the examples of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without creative work should all fall within the scope of protection of the present invention.

[0067] The implementation scenarios of this example include the frequent changes in the network topology of satellite Internet due to factors such as solar eclipse and satellite movement. The information exchange load between satellites is heavy, and it is necessary to update the network topology in a timely manner and reduce the transmission load to ensure the quality of communication services and provide an efficient and reliable service environment for other onboard services.

[0068] Embodiment 1, the satellite Internet time-varying routing method provided by the present invention.

[0069] Reference Figure 1 The implementation steps of this example include the following:

[0070] Step 1: Initialize the satellite node.

[0071] The queue for sending the initial topology prediction message is empty, and the queue for processing the initial message is empty;

[0072] Set the topology prediction message sending threshold to T threshold, set the orbital parameters of the satellite node {r, e, i, Ω, δ, v}, where r is the semi-major axis of the satellite node, e is the eccentricity of the satellite node, i is the orbital inclination of the satellite node, Ω is the right ascension of the ascending node of the satellite node, δ is the argument of perigee of the satellite node, and ν is the mean anomaly of the satellite node.

[0073] Step 2: Calculate the satellite's angular velocity ω, orbital period T, and true anomaly θ at any time. t and spatial position (x t ,y t , z t ).

[0074] 2.1) Based on the radius of the earth R and the orbital height of the satellite h s Calculate the semi-major axis r of the satellite node:

[0075] r=R+h s ;

[0076] 2.2) Calculate the satellite's angular velocity w based on the semi-major axis r:

[0077]

[0078] Among them, G is the gravitational constant, M is the mass of the earth;

[0079] 2.3) Calculate the orbital period T based on the satellite's angular velocity w:

[0080]

[0081] 2.4) Calculate the true anomaly θ of the satellite at any time t and spatial position (x t ,y t , z t ):

[0082] 2.4.1) Calculate the true anomaly θ of the satellite at any time based on the true anomaly θ0 and angular velocity ω of the satellite at the initial time t :

[0083] θ t =θ0+ω t ;

[0084] 2.4.2) According to the orbital plane rotation angle θ of the satellite at any time t and the semi-major axis r of the satellite node to calculate the satellite coordinates (x w ,y w ):

[0085] x w = r cosθ t ,y w = r sinθt ;

[0086] 2.4.3) According to the satellite coordinates (x w ,y w ) Calculate the satellite's spatial position (x t ,y t , z t ):

[0087]

[0088] Among them, Ω is the right ascension of the ascending node; i is the orbital inclination.

[0089] It should be noted that the satellite's spatial position can also be calculated based on the radial distance, which is implemented as follows:

[0090] First, the radial distance α of the satellite is calculated according to the semi-major axis r and eccentricity e of the satellite node:

[0091] α = r(1-e cos(E)), where E is the satellite node's anomaly angle;

[0092] Secondly, the orbital plane coordinates (x′, y′) of the satellite are calculated according to the true anomaly θ of the satellite:

[0093] x′=αcosθ, y′=αsinθ;

[0094] Finally, the satellite’s spatial position (x, y, z) is calculated from the satellite’s coordinates (x′, y′) in the orbital plane:

[0095]

[0096] Among them, Ω is the right ascension of the satellite's ascending node; i is the satellite's orbital inclination.

[0097] Step 3: Initialize the inter-satellite link set of the satellite node.

[0098] The intersatellite link includes the link for establishing communication between satellites, the link cost value, and the starting node and destination node of the link, which are used to describe the information of the link in the satellite Internet.

[0099] Initialize the intersatellite link set of the satellite node, expressed as:

[0100] {(l i , cost i , S i , S j )}, i, j∈[0,n]

[0101] Among them, l i represents the i-th link in the satellite network, cost irepresents the cost value of the i-th link, S i and S j represents the starting satellite node and the destination satellite node of the link, and n is the number of satellite nodes in the satellite Internet.

[0102] Step 4: construct a link on / off schedule for the satellite node and send it to the satellite node.

[0103] 4.1) The ground station sets the satellite node's intersatellite link set {(l i , cost i , S i , S j )}, i, j∈[0, n] and the satellite node’s angular velocity ω, orbital period T, true anomaly θ t and spatial position (x t ,y t , z t ) as input data, and output the links in the Internet, the link cost value, the link connection status, the time when the link changes, and the starting node and destination node of the link after simulation by the satellite toolkit STK;

[0104] 4.2) The output after simulation by the satellite toolkit STK is used to form a link on-off schedule of the satellite node, which is used to describe the link information and link on-off time when the satellite Internet topology changes, which can be expressed as:

[0105]

[0106] Among them, l i represents the i-th link, cost i Indicates the cost value of the i-th link, state i represents the state of the i-th link, Δt i Indicates the change time of the link, S i and S j They represent the starting node and destination node of the link respectively.

[0107] It should be noted that the satellite link on-off schedule can also be calculated through the orbital plane coordinates and connection relationship, which is implemented as follows:

[0108] First, according to the orbital plane coordinates of the satellite (x w ,y w ) Determine the neighbor nodes of the satellite node, such as Figure 3 As shown in the figure, from the basic configuration of satellite Internet, each satellite node without boundary has four neighbor nodes, namely, satellites S in the same orbit. a (x w -μ,y w ), S b (xw +μ,y w ), different orbit satellite S c (x w ,y w -μ), S d (x w ,y w +μ), where μ is the unit length of the satellite network orbital coordinates;

[0109] Secondly, according to the periodic motion of the satellite, the satellite coordinates are calculated every T time, and the neighbor nodes of the satellite node are recorded and compared with the neighbor nodes of the previous cycle. When the neighbor nodes of the satellite change, the link data of this change is recorded, which is recorded as

[0110] Finally, after calculating the orbital coordinates of the satellite nodes of all periods in sequence, the recorded link change data are constructed into a link on-off schedule.

[0111] Step 5: After receiving the link on / off schedule from the ground station, the satellite node will traverse the data of each link in turn. Generates topology prediction messages for links at different times.

[0112] 5.1) Satellite nodes obtain data from the link on / off schedule Determine whether the satellite node is equal to S i :

[0113] If the two are not equal, skip the data and continue to read the next data until the link on / off table traversal is completed;

[0114] If the two are equal, read the corresponding link information l i , link cost value cost i , link state value state i and link change time Δt i , generate a topology prediction message;

[0115] 5.2) The topology prediction message structure of the present invention is as follows Figure 2 As shown in the figure, it adds a link change time attribute on top of the basic structure of the network layer reachability information NLRI. This attribute is a 32-bit integer data type and is used by satellite nodes to set timers to calculate virtual routes. Each topology prediction message contains only one link status information parameter. The topology prediction message needs to be merged in the routing control message and sent. A routing control message can contain multiple topology prediction messages. When sending, one or more topology prediction messages are merged in the routing control message in descending time order and sent.

[0116] It should be noted that the routing control message is a message specified by the network layer of the satellite Internet routing protocol. It uses the IP protocol for communication to maintain the network topology and shortest path tree of the satellite Internet. Since the movement of satellites is periodic, satellite nodes are set to periodically send routing control messages to maintain the topology of the entire network.

[0117] Step 6: The satellite node calculates the time t at which the routing control message is sent. Route , and determine the time when the routing control message is sent.

[0118] 6.1) Satellite nodes use the system clock value T c And the sending cycle of routing control message T Route Calculate the time t at which the routing control message is sent Route :

[0119]

[0120] 6.2) Satellite nodes predict the link change time Δt in the message based on the topology i The time t when the routing control message is sent Route , calculate the time difference ΔT i :

[0121] ΔT i =Δt i -t Route ;

[0122] 6.3) Set ΔT i The topology prediction message sending threshold T threshold Compare and determine the time when the routing control message is sent:

[0123] If ΔT i ≤T threshold , a routing control message is generated, and the current topology prediction message is merged into the routing control message. If the topology prediction message to be sent sequence is not empty at this time, all topology prediction messages in the sequence are merged into the routing control message, stored in the message processing queue, and sent to the neighboring nodes around the satellite node, flooding the message in the limited area;

[0124] If ΔT i >T threshold , the topology prediction message is added to the topology prediction message to be sent sequence. When the routing control message is sent periodically, all the topology prediction messages in the sequence are taken out, merged into the routing control message, stored in the message processing queue of the satellite node, and sent to the neighboring nodes around the satellite node, flooding the message in the limited area.

[0125] Step 7: The satellite node receives the routing control message, stores it in the message processing queue, and determines whether to send the message to the neighboring satellite node based on whether the AS number in the message is equal to the area ID to which the node belongs.

[0126] 7.1) Satellite Internet regional division.

[0127] According to the neighbor relationship between a single satellite and its left node and right node on the same orbit and the upper node and lower node on the different orbit, a grid topology is formed, and the grid topology is regarded as the basic topological unit of the satellite network; the scope of the grid topology is then expanded to form a general satellite Internet area, such as Figure 3 As shown;

[0128] It should be noted that the satellite Internet area can also be divided according to the frequency segment planning by satellite nodes according to their frequency segments. Satellites with the same frequency segment form an area. Satellite nodes only transmit information within the area, and only regional boundary nodes can communicate with satellites in other areas.

[0129] 7.2) Select the orbital position information of any satellite node in the satellite Internet area (x o ,y o ) means, where x o Indicates the xth satellite node in the satellite network o On the orbital plane, y o Indicates that the satellite node is the yth node of the orbital plane o satellites;

[0130] 7.3) Calculate the node area ID based on the satellite node's orbital position information (x0, y0):

[0131]

[0132] Among them, M o is the number of satellite Internet orbits, h is the number of horizontal orbital planes in the area, and l is the number of vertical orbital planes in the area;

[0133] 7.4) The satellite node compares the AS number in the control message with the calculated area ID:

[0134] If the AS number = area ID, the routing control message is stored in the satellite node's message processing queue and the message is forwarded to the surrounding neighbor satellite nodes;

[0135] If the AS number ≠ area ID, stop forwarding the routing control message and discard it.

[0136] Step 8: The satellite node takes out the routing control message from the message processing queue, parses the topology prediction message therein, and determines the start time of the virtual routing calculation.

[0137] 8.1) Satellite node obtains link information in topology prediction message l i , link change time Δt i , link cost value cost i , link state i , Link start node S i and link destination node S j , and according to Δt i To arrange the update order of the satellite node routing table, the result is as follows Figure 4 As shown;

[0138] 8.2) Satellite node determines the virtual routing calculation starting time Δt i :

[0139] ΔT i =Δt i -T pre

[0140] Among them, T pre Virtual routing calculation time set for satellite nodes, Δt i The link change time obtained after the satellite node parses the topology prediction message.

[0141] Step 9: The satellite node calculates the virtual routing table at the link change time Δt i Switch the routing table and send the routes to the basic network layer.

[0142] 9.1) Satellite nodes set virtual route calculation timer, triggering time is virtual route calculation start time Δt i , get the satellite node's virtual routing table, which is an independent routing table on the satellite node, storing the routing information after the satellite node link changes, and cannot be used directly to send routes;

[0143] 9.2) The satellite node sets the routing table switching timer, and the triggering time is the link change time Δt i , replace the satellite node's routing table with a virtual routing table, and send the route to the satellite node's basic network layer.

[0144] Embodiment 2, the satellite Internet time-varying routing system provided by the present invention.

[0145] Reference Figure 5 The system modules of this example include: a topology prediction message generation module 1, a topology prediction message sending module 2, a limited area flooding module 3 and a virtual routing calculation module 4, and its working principle is as follows:

[0146] After the system is started, the topology prediction message generation module 1 receives the link on-off schedule sent by the ground station, parses the link change data therein and generates a topology prediction message, and passes the message to the topology prediction message sending module 2; the topology prediction message sending module 2 determines the message sending time according to the difference between the link change time and the routing control message, merges the topology prediction message into the routing control message in the satellite Internet communication protocol and sends it to the surrounding neighbor nodes, and passes the message to the limited area flooding module 3; after receiving the message, the limited area flooding module 3 determines the equality between the AS number of the message and the ID of the area to which the node belongs: if the two are not equal, the message is discarded; if the two are equal, the message continues to be sent to the surrounding neighbor nodes and the virtual routing calculation module 4 is called; the virtual routing calculation module 4 determines the starting time of the virtual routing calculation, sets a timer to perform the virtual routing calculation, replaces the routing table of the satellite node with the virtual routing table at the link change time, and sends it to the basic network layer of the satellite node.

[0147] Embodiment 3, the electronic device provided by the present invention.

[0148] Reference Figure 6 , the electronic device of this example includes a processor, a memory, an input / output interface and a communication interface, wherein:

[0149] The processor is implemented by a general-purpose central processing unit CPU, a microprocessor, an application-specific integrated circuit ASIC, or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification;

[0150] The memory can be implemented in the form of a read-only memory ROM, a random access memory RAM, a static storage device SRAM, a dynamic storage device DRAM, etc. It can store the satellite Internet time-varying routing system program provided by the present invention, and be called and executed by the processor;

[0151] The input / output interface is used to connect the input / output module to realize data input and output;

[0152] The communication interface is used to connect the communication module to realize the communication interaction between the device and the ground station device. The communication module can communicate by wire or by wireless;

[0153] It should be noted that, although the above device only shows a processor, a memory, an input / output interface, and a communication interface, in the specific implementation process, the device may also include other components necessary for normal operation. In addition, it can be understood by those skilled in the art that the above device may also only include components necessary for implementing the embodiments of the present specification, and does not necessarily include all the components shown in the figure.

[0154] Embodiment 4, the computer readable medium provided by the present invention.

[0155] This embodiment provides a computer-readable medium, which stores multiple instructions. The instructions can be loaded by a processor to execute the steps in any satellite Internet time-varying routing method provided in the embodiments of the present invention.

[0156] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and any method or technology can be used to implement information storage; the information can be a computer-readable instruction, a data structure, a module of a program, or other data. The computer storage medium includes but is not limited to phase change memory PRAM, static random access memory SRAM, dynamic random access memory DRAM, other types of random access memory RAM, read-only memory ROM, electrically erasable programmable read-only memory EEPROM, flash memory or other memory technology, which can be used to store information that can be accessed by a computing device.

[0157] It should be noted that the step numbers in the specification and claims of the present invention are only for a clear description of the implementation scheme of the present invention to facilitate understanding, and the order of the step numbers is not limited.

Claims

1. A time-varying routing method for satellite Internet, characterized in that: include: (1) Initialize the satellite nodes, initialize the topology prediction message to be sent sequence to be empty, initialize the message processing queue to be empty, and set the topology prediction message sending threshold to T threshold , initialize the orbit parameters of the satellite node, calculate the angular velocity ω, orbit period T, true anomaly θ of the satellite node t and spatial position (x t ,y t , z t ); (2) Initialize the inter-satellite link set of the satellite node. The ground station initializes the inter-satellite link set {(l i , cost i , S i , S j )}, the angular velocity ω of the satellite node, the orbital period T, the true anomaly θ t and spatial position (x t ,y t , z t ), obtain the satellite link on-off schedule through the satellite toolkit STK simulation, and send the link on-off schedule to the satellite node; (3) After receiving the link on / off schedule, the satellite node generates a topology prediction message, which includes the link change time, link change status, link cost value, link start node and destination node information; (4) Obtain the sending time of the routing control message from the satellite's system clock, obtain the link change time from the topology prediction message, calculate the difference between the two to determine the sending time of the topology prediction message, and send it to the neighboring satellite node; (5) After receiving the routing control message, the satellite node stores it in the message processing queue and floods the routing control message in the limited area; (6) Take out the routing control message from the satellite node's message processing queue, parse the topology prediction message therein, arrange the order of satellite node routing table updates according to the link change time, calculate the virtual routing table entry before the link changes, use the virtual routing table entry to switch the satellite node's routing table entry at the link change time, and send the route.

2. The method according to claim 1, characterized in that: In (1), the orbital parameters of the satellite node are initialized, and the angular velocity ω, orbital period T, and true anomaly θ of the satellite node are calculated. t and spatial position (x t ,y t , z t ), whose implementation includes: (1a) Initialize the satellite node orbit parameters {r, e, i, Ω, δ, v}, where α is the semi-major axis of the satellite node, e is the eccentricity of the satellite node, i is the orbit inclination of the satellite node, Ω is the right ascension of the ascending node of the satellite node, δ is the argument of perigee of the satellite node, and v is the mean anomaly of the satellite node; (1b) Calculate the satellite’s angular velocity ω and orbital period T: According to the radius R of the earth and the orbital height h of the satellite s Calculate the semi-major axis of the satellite node r = R + h s ; Calculate the angular velocity of the satellite based on the semi-major axis r Among them, G is the gravitational constant, M is the mass of the earth; Calculate the orbital period based on the satellite's angular velocity ω (1c) Calculate the true anomaly θ of the satellite at any time t and spatial position (x t ,y t , z t ): The true anomaly θ of the satellite at any time is calculated based on the true anomaly θ0 and angular velocity ω of the satellite at the initial time. t =θ0+ωt, where t is any time; According to the orbital plane rotation angle θ of the satellite at any time t and the semi-major axis r of the satellite node to calculate the satellite coordinates (x w ,y w ): x w =r cosθ t ,y w =r sinθ t ; According to the satellite coordinates of the orbital plane (x w ,y w ) Calculate the satellite's spatial position (x t ,y t , z t ): Among them, Ω is the right ascension of the ascending node; i is the orbital inclination.

3. The method according to claim 1, characterized in that The inter-satellite link set of the satellite node is initialized in (2), and the ground station is based on the inter-satellite link set {(l i , cost i , S i , S j )}, the angular velocity w of the satellite node, the orbital period T, the true anomaly θ t and spatial position (x t ,y t , z t ), and obtain the satellite link on-off schedule through satellite toolkit STK simulation, including: (2a) Initialize the intersatellite link set of the satellite node, expressed as: {(l i ,cost i ,S i ,S j )},i,j∈[0,n] Among them, l i represents the i-th link in the satellite network, cost i represents the cost value of the i-th link, S i and S j represents the starting satellite node and the destination satellite node of the link, and n is the number of nodes in the satellite Internet; (2b) The ground station sets the inter-satellite link set of the satellite node {(l i , cost i , S i , S j )} and the satellite node's angular velocity ω, orbital period T, true anomaly θ t and spatial position (x t ,y t , z t ) is used as the input data of the satellite toolkit STK. After simulation, the link on / off schedule of the satellite node is output, which is expressed as: Among them, l i represents the i-th link, cost i Indicates the link cost value, state i Indicates the link status, Δt i Indicates the link change time, S i and S j Represent the starting node and destination node of the link respectively.

4. The method according to claim 1, characterized in that: In (3), the satellite node generates a topology prediction message after receiving the link on / off schedule, and its implementation includes: (3a) Satellite nodes obtain data from the link on / off schedule (3b) Determine whether the satellite node is equal to S i : If the two are not equal, skip the data and continue to read the next data until the link on / off table traversal is completed; If the two are equal, read the corresponding link information l i , link cost value cost i , link state value state i and link change time Δt i , generate a topology prediction message. The topology prediction message structure is based on the network layer reachability information NLRI structure and adds a link change time attribute. This attribute is a 32-bit integer data type and is used to set the timer to calculate the virtual routing table of the satellite node.

5. The method according to claim 1, characterized in that The calculation of the difference between the two in (4) to determine the time of sending the topology prediction message includes: (4a) Based on the satellite node system clock value T c And the sending cycle of routing control message T Route Calculate the time t at which the routing control message is sent Route : (4b) Predict the link change time Δt in the message based on the topology i The time t when the routing control message is sent Route , calculate the difference ΔT between the two i : ΔT i =Δt i -t Route ; (4c) The difference ΔT i The topology prediction message sending threshold T set by the satellite node threshold For comparison: If ΔT i ≤T threshold , the satellite node immediately generates a routing control message and merges the topology prediction message, and sends it to the neighboring satellite node; If ΔT i >T threshold , then the topology prediction message is stored in the topology prediction message to be sent sequence, and at the time of sending the routing control message, all the topology prediction messages in the sequence are merged into the routing control message and sent to the neighboring satellite node.

6. The method according to claim 1, characterized in that The implementation of flooding the routing control message in the limited area in (5) includes: (5a) According to the orbital position of the satellite node (x o ,y0) information calculation satellite node area ID: Among them, M o is the number of satellite Internet orbits, h is the number of horizontal orbital planes in the area, and l is the number of vertical orbital planes in the area; (5b) The satellite node compares the AS number in the routing control message with the calculated area ID: If the AS number = area ID, the routing control message is stored in the satellite node's message processing queue and the message is forwarded to the neighboring satellite node; If the AS number ≠ area ID, stop forwarding the routing control message and discard the message.

7. The method according to claim 1, characterized in that The implementation of arranging the order of updating the routing table according to the time of link change in (6) includes: (6a) The satellite node obtains the routing control message from the message processing queue, parses the topology prediction message in the routing control message, and obtains the link information in the message. i , link change time Δt i , link cost value cost i , link state i , Link start node S i and link destination node S j ; (6b) The satellite node determines the virtual route calculation start time ΔT i : ΔT i =Δt i -T pre Among them, T pre The maximum virtual route calculation time set for satellite nodes, (6c) Satellite node at ΔT i Set a timer at every moment to perform virtual routing calculation, obtain the virtual routing table of the satellite node, and i The satellite node's routing table is always replaced with a virtual routing table that is sent to the satellite node's basic network layer.

8. A time-varying routing system for satellite Internet, characterized in that: include: A topology prediction message generation module is used for the satellite node to receive the link on / off schedule sent by the ground station, parse the link change data therein and generate a topology prediction message; A topology prediction message sending module is used to calculate the difference between the topology prediction message link change time and the routing control message sending time, determine the message sending time, merge the topology prediction message into the routing control message and send it to the surrounding neighbor nodes; The limited area flooding module is used to determine the sending range of the routing control message after the satellite node receives the routing control message, that is, to compare the AS number of the routing control message with the area ID to which the satellite node belongs. If the two are equal, the message will continue to be sent to the surrounding neighboring nodes, otherwise the message will be discarded; Virtual routing calculation module, used by satellite nodes to parse topology prediction messages and set timers for virtual routing calculations, and read link change time Δt in topology prediction messages i , to determine the virtual routing calculation start time ΔT i , and set a timer at this moment to perform virtual routing calculation. i The satellite node's routing table is always replaced with a virtual routing table and sent to the satellite node's basic network layer.

9. An electronic device comprising a processor, a memory, an input / output device, a communication interface, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the time-varying routing method for satellite Internet is implemented as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the time-varying routing method for satellite Internet as described in any one of claims 1 to 7.

Images