Intersatellite link determination method, device and electronic equipment

Abstract

The present application provides an intersatellite link determination method, device and electronic device, the method comprising: determining the constraints of the intersatellite link; the constraints include: geometric visibility conditions, link pointing change constraints and intersatellite communication connectivity conditions; based on the geometric visibility conditions and link pointing change constraints, constructing the intersatellite maximum distance matrix; based on the intersatellite maximum distance matrix and the intersatellite communication connectivity conditions, constructing the intersatellite link connectivity matrix containing the link information between the constellation satellites; based on the intersatellite link connectivity matrix, using the end-to-end shortest path transmission SPF protocol, and using the Dijkstra algorithm to determine the data transmission path between any two satellites in the constellation. The present application determines the minimum transmission path of the intersatellite link by determining the constraints, constructing the intersatellite maximum distance matrix and the intersatellite link connectivity matrix, and solving the minimum distance, which is suitable for the analysis scenario of a hybrid heterogeneous low-orbit giant constellation.

Description

Technical Field

[0001] The present application relates to the field of satellite technology, and in particular to an inter-satellite link determination method, device and electronic equipment. Background Art

[0002] Establishing intersatellite links in a constellation has many advantages, such as low communication delay, low path loss, and intersatellite data transmission does not rely on ground networks. Some constellation plans have claimed that they will be equipped with broadband laser intersatellite links. As a huge space-based information network platform, each satellite node in the giant constellation is not an independent individual, but works together to maximize the overall function of the system. Therefore, intersatellite communication capabilities will become an essential attribute of giant constellations, and intersatellite link design will also become an indispensable part of giant constellation design. At present, relevant personnel have studied the necessity of installing intersatellite links in large low-orbit Internet constellations, and concluded that intersatellite links greatly reduce transmission delays, avoid the adverse effects of bad weather, and their data throughput is 3 times that of space systems without intersatellite links.

[0003] For the problem of inter-satellite link design, previous studies were mainly based on medium and high orbit satellite systems. For example, the connectivity and robustness of inter-satellite links were analyzed using graph theory, and simulation analysis was performed based on Walker. The inter-satellite link design problem of heterogeneous GNSS systems was studied based on laser links and Ka high-speed links. The link design principles include shortest path, traffic load balancing, and minimum number of routing switches. With the maximum PDOP value as the goal, the MOSA algorithm was used to solve the optimal solution for dynamic links, and simulation analysis was performed based on the BDS system. In summary, the research on inter-satellite link design for low-orbit giant constellations is relatively scarce and has high research value. Summary of the invention

[0004] The purpose of the present application is to provide an inter-satellite link determination method, device and electronic device, which determine the minimum transmission path of the inter-satellite link by determining constraint conditions, constructing an inter-satellite maximum distance matrix and an inter-satellite link connectivity matrix, and solving the minimum distance, and is suitable for the analysis scenario of a hybrid heterogeneous low-orbit giant constellation.

[0005] In a first aspect, the present application provides an inter-satellite link determination method, the method comprising: determining the constraints of the inter-satellite links; the constraints comprising: geometric visibility conditions, link pointing change constraints and inter-satellite communication connectivity conditions; based on the geometric visibility conditions and the link pointing change constraints, constructing an inter-satellite maximum distance matrix; each element in the inter-satellite maximum distance matrix represents the maximum distance between two satellites; based on the inter-satellite maximum distance matrix and the inter-satellite communication connectivity conditions, constructing an inter-satellite link connectivity matrix containing link information between constellation satellites; based on the inter-satellite link connectivity matrix, adopting an end-to-end shortest path transmission SPF protocol, and using the Dijkstra algorithm to determine the data transmission path between any two satellites in the constellation.

[0006] Furthermore, the above-mentioned geometric visibility conditions include:

[0007] ;

[0008] Among them, the vector Respectively represent the position vectors of the two satellites in the ECI coordinate system; h is the distance from the two satellites’ line of sight to the center of the earth; θ It represents the angle between the two satellites and the center of the earth;

[0009] Link pointing change constraints include:

[0010] The constraints on the rotation angle and angular velocity of the intersatellite link are:

[0011] ; ;

[0012] in , They are the maximum azimuth, elevation and low beam rotation angles that the onboard communication equipment can provide. , is the beam rotation angular velocity in the azimuth and elevation directions of the link, and its upper limits are , ; The azimuth of the intersatellite link pointing in the satellite's coordinate system and height angle The calculation formula is:

[0013] ; ; ;

[0014] in, is the direction vector of the coordinate axis of the body coordinate system with the center of mass of satellite m as the origin in the ECI coordinate system, is the direction vector of the intersatellite link between the two satellites, is the link vector in the satellite body coordinate system Projection on a plane; , is the position vector of the satellite in the ECI coordinate system.

[0015] Furthermore, the above intersatellite communication connectivity condition includes: a connectivity judgment matrix, which is expressed as:

[0016] ; ;

[0017] Where A is the adjacency matrix; Indicates i Satellites and j The connection status between satellites. If there is an intersatellite link, ,otherwise, ; is the total number of satellites in the heterogeneous mega-constellation;

[0018] The necessary and sufficient conditions for the constellation to be fully connected are: the matrix All elements in are not 0, and the elements Indicates i Satellite connected to j The number of different paths for the satellites.

[0019] Furthermore, the step of constructing the inter-satellite maximum distance matrix based on the geometric visibility condition and the link pointing change constraint condition includes: assuming that multiple inter-satellite links are established on each satellite, calculating the maximum distance between any two satellites in the constellation, and obtaining the inter-satellite maximum distance initial matrix :

[0020] ;

[0021] in, ;

[0022] ; ;

[0023] in, is the right ascension difference of the ascending nodes of the two satellites; is the phase difference between the two satellites; , are the orbital inclinations of the two satellites respectively; is the radius of the Earth; is the satellite’s orbital altitude;

[0024] Determine whether any two satellites meet the geometric visibility conditions and link pointing change constraints at the same time, and convert the initial matrix The corresponding position elements of two satellites that do not meet the two conditions at the same time are recorded as 0, and the maximum distance matrix between satellites is obtained. .

[0025] Furthermore, the above-mentioned step of constructing an intersatellite link connectivity matrix containing link information between constellation satellites based on the intersatellite maximum distance matrix and the intersatellite communication connectivity condition includes: constructing an initial adjacency matrix that characterizes whether there is an intersatellite link between satellites; the initial adjacency matrix corresponds to the element position in the intersatellite maximum distance matrix one by one; taking the first row of the intersatellite maximum distance matrix as the current row, and performing the following assignment and statistical steps: assigning values ​​to the initial adjacency matrix based on the element data of the current row to obtain an intermediate adjacency matrix; counting the sum of the elements of each row and the sum of the elements of each column in the intermediate adjacency matrix; if the sum of the elements of a row or a column is If the sum of the column elements is equal to the specified number, the subsequent assignment and statistical steps of the row or column will not be performed; it is determined whether the sum of the elements of all the current rows and columns reaches the specified number; if not, the next row of the inter-satellite maximum distance matrix is ​​used as the current row again, and the assignment judgment step is continued until the sum of the elements of all the current rows and columns reaches the specified number, and the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; if yes, the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; the inter-satellite link connectivity matrix meets the inter-satellite communication connectivity conditions.

[0026] Furthermore, the step of assigning values ​​to the initial adjacency matrix based on the element data of the current row to obtain the intermediate adjacency matrix includes: sorting the element data of the current row from small to large, recording the first position of the previously specified number of minimum element data in the inter-star maximum distance matrix; determining the second position corresponding to the first position and the third position symmetrical to the second position in the initial adjacency matrix; and assigning the elements of the second position and the third position both to 1 to obtain the intermediate adjacency matrix.

[0027] Furthermore, the above-mentioned step of determining the data transmission path between any two satellites in the constellation based on the inter-satellite link connectivity matrix, adopting the end-to-end shortest path transmission SPF protocol, and using the Dijkstra algorithm includes: dividing the inter-satellite link connectivity matrix into a first set including the source node and a second set including all remaining nodes; looping the following steps until the second set is an empty set: searching for the target node with the smallest distance to the source node in the first set according to the distance information between any two satellites at a certain moment in the weight matrix, and adding the target node to the first set, while removing the target node from the second set; the weight matrix is ​​a matrix composed of the distance values ​​between any two satellites; judging whether the distance between the target node added in the first set and the current source node is less than the current distance value corresponding to the current source node, and if so, applying the distance between the target node and the current source node to update the current distance value corresponding to the current source node in the weight matrix, otherwise not updating.

[0028] In the second aspect, the present application also provides an inter-satellite link determination device, the device comprising: a condition determination module, used to determine the constraints of the inter-satellite link; the constraints include: geometric visibility conditions, link pointing change constraints and inter-satellite communication connectivity conditions; a first matrix construction module, used to construct an inter-satellite maximum distance matrix based on the geometric visibility conditions and the link pointing change constraints; each element in the inter-satellite maximum distance matrix represents the maximum distance between two satellites; a second matrix construction module, used to construct an inter-satellite link connectivity matrix containing link information between constellation satellites based on the inter-satellite maximum distance matrix and the inter-satellite communication connectivity conditions; a transmission path determination module, used to determine the data transmission path between any two satellites in the constellation based on the inter-satellite link connectivity matrix, using the end-to-end shortest path transmission SPF protocol, and using the Dijkstra algorithm.

[0029] In a third aspect, the present application further provides an electronic device, comprising a processor and a memory, wherein the memory stores computer executable instructions that can be executed by the processor, and the processor executes the computer executable instructions to implement the method described in the first aspect above.

[0030] In a fourth aspect, the present application further provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the method described in the first aspect above.

[0031] In the intersatellite link determination method, device and electronic device provided by the present application, the constraints of the intersatellite link are first determined; the constraints include: geometric visibility conditions, link pointing change constraints and intersatellite communication connectivity conditions; then, based on the geometric visibility conditions and link pointing change constraints, the intersatellite maximum distance matrix is ​​constructed; each element in the intersatellite maximum distance matrix represents the maximum distance between two satellites; based on the intersatellite maximum distance matrix and the intersatellite communication connectivity conditions, an intersatellite link connectivity matrix containing link information between constellation satellites is constructed; finally, based on the intersatellite link connectivity matrix, the end-to-end shortest path transmission SPF protocol is adopted, and the data transmission path between any two satellites in the constellation is determined by the Dijkstra algorithm. The present application first determines the basic constraints for establishing intersatellite links by analyzing the relative position relationship between satellites, which are satellite geometric visibility conditions, link pointing change conditions, and intersatellite communication full connectivity conditions; then, the intersatellite link of each satellite is established based on the principle of minimum intersatellite maximum distance, ensuring the stability of the link and avoiding frequent link reconstruction during data transmission; finally, based on the SPF protocol, the transmission path of any two satellites is determined by the Dijkstra algorithm. It is suitable for the analysis scenarios of hybrid heterogeneous low-orbit giant constellations. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A flowchart of an intersatellite link determination method provided in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of satellite geometric visibility conditions provided in an embodiment of the present application;

[0035] Figure 3 A diagram of simulation results of an intersatellite link design provided in an embodiment of the present application;

[0036] Figure 4 A structural block diagram of an inter-satellite link determination device provided in an embodiment of the present application;

[0037] Figure 5 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The technical solution of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0039] The high dynamics of LEO satellites determine that the relative positions of satellites in the constellation change dramatically, making frequent switching of satellite-to-ground and inter-satellite links inevitable. Link switching has many negative effects on inter-satellite data transmission. First, the large amount of pathfinding information generated by link switching can easily cause network congestion. Second, the high latency and high data loss rate of satellite rerouting greatly reduce the utilization of the network. Third, the recapture, aiming, and tracking of satellites pose major technical challenges and hinder the smooth operation of the inter-satellite communication network.

[0040] Based on this, the embodiments of the present application provide an inter-satellite link determination method, device and electronic device, which determine the minimum transmission path of the inter-satellite link by determining constraints, constructing an inter-satellite maximum distance matrix and an inter-satellite link connectivity matrix, and solving the minimum distance, and are suitable for the analysis scenario of a hybrid heterogeneous low-orbit giant constellation.

[0041] To facilitate understanding of this embodiment, a method for determining an inter-satellite link disclosed in an embodiment of the present application is first introduced in detail.

[0042] Figure 1 A flowchart of a method for determining an intersatellite link provided in an embodiment of the present application, the method comprising the following steps:

[0043] Step S102, determining the constraints of the intersatellite link; the constraints include: geometric visibility conditions, link direction change constraints and intersatellite communication connectivity conditions;

[0044] The establishment of intersatellite links needs to meet geometric visibility conditions, the link pointing change amplitude and rate must be within the tracking and aiming capabilities of the intersatellite communication equipment, and the constellation must meet the intersatellite communication full connectivity conditions. The specific constraints are described in detail later.

[0045] Step S104, constructing an inter-satellite maximum distance matrix based on geometric visibility conditions and link pointing change constraints; each element in the inter-satellite maximum distance matrix represents the maximum distance between two satellites;

[0046] Step S106, constructing an inter-satellite link connectivity matrix including link information between constellation satellites based on the inter-satellite maximum distance matrix and the inter-satellite communication connectivity condition;

[0047] The specific implementation process of the above two steps will be described in detail later. The intersatellite link connectivity matrix is ​​a matrix including 0 and 1, and the position of 1 represents that two satellites can establish an intersatellite link.

[0048] Step S108, based on the inter-satellite link connectivity matrix, using the end-to-end shortest path transmission SPF protocol and using the Dijkstra algorithm to determine the data transmission path between any two satellites in the constellation.

[0049] The Shortest Path First (SPF) protocol is a protocol that ensures the shortest data transmission path between satellites.

[0050] The Dijkstra algorithm is a shortest path algorithm from one vertex to the rest of the vertices, and solves the shortest path problem in a weighted graph. The main feature of the Dijkstra algorithm is that it starts from the starting point and uses a greedy algorithm strategy to traverse the adjacent nodes of the vertex that is closest to the starting point and has not been visited each time until it reaches the end point.

[0051] The intersatellite link determination method provided in the embodiment of the present application is an intersatellite link design method suitable for low-orbit hybrid heterogeneous giant constellations. First, by analyzing the relative position relationship between satellites, the basic constraints for establishing intersatellite links are determined, namely, satellite geometric visibility conditions, link pointing change conditions, and intersatellite communication full connectivity conditions; then, the intersatellite link of each satellite is established based on the principle of minimum maximum distance between satellites, ensuring the stability of the link and avoiding frequent link reconstruction during data transmission; finally, based on the SPF protocol, the Dijkstra algorithm is used to determine the transmission path of any two satellites.

[0052] The embodiment of the present application also provides another inter-satellite link determination method, which is implemented on the basis of the above embodiment; this embodiment focuses on describing the details of the constraint conditions, the inter-satellite link determination process and the transmission path determination process.

[0053] Step 1: Determine the constraints of the intersatellite link design. The establishment of the intersatellite link needs to meet the geometric visibility conditions, the link pointing change range and rate must be within the tracking and aiming capabilities of the intersatellite communication equipment, and the constellation must meet the intersatellite communication full connectivity conditions;

[0054] Step 1.1: Determine the inter-satellite visibility constraints;

[0055] The basic condition for two satellites in LEO orbit to establish an intersatellite link is geometric visibility in space. Figure 2 The figure shows the spatial geometric relationship between the two satellites. are the position vectors of satellites A and B in the ECI coordinate system, and h is the distance from the line of sight of the two satellites to the center of the earth O.

[0056] Then, the visibility condition of any two satellites in space can be expressed as follows: if h is greater than the radius of the earth, then the two satellites can see each other, and h is calculated as:

[0057] ;

[0058] Among them, the vector Respectively represent the position vectors of the two satellites in the ECI coordinate system; h is the distance from the two satellites’ line of sight to the center of the earth; θ It represents the angle between the two satellites and the center of the earth;

[0059] Step 1.2: Determine the link direction change constraint conditions;

[0060] As the relative positions of satellites on different orbital planes are constantly changing, the pointing direction of the satellite antennas equipped with intersatellite links is constantly changing. Restricted by the accuracy and complexity of intersatellite communication equipment, the rotation angle and angular velocity of the antenna need to change within a certain range during the aiming and tracking process.

[0061] Assuming that a link is established between satellite m and satellite n, the azimuth of the intersatellite link in the satellite's own coordinate system is and height angle The calculation formula is:

[0062] ;

[0063] in, is the direction vector of the coordinate axis of the body coordinate system with the center of mass of satellite m as the origin in the ECI coordinate system, is the direction vector of the intersatellite link between the two satellites, is the link vector in the satellite body coordinate system Projection on a plane. , They are calculated as:

[0064] ;

[0065] ;

[0066] in, , is the position vector of the satellite in the ECI coordinate system.

[0067] Then, the constraints of the rotation angle and angular velocity of the intersatellite link are:

[0068] ; ;

[0069] in , They are the maximum azimuth, elevation and low beam rotation angles that the onboard communication equipment can provide. , is the beam rotation angular velocity in the azimuth and elevation directions of the link, and its upper limits are , .

[0070] Step 1.3: Establish intersatellite communication connectivity conditions;

[0071] In order to realize the communication between satellite nodes connected by intersatellite links between any two places in the world, the design of constellation intersatellite links needs to meet the global connectivity requirements. It is an effective means to use the adjacency matrix in graph theory to describe and analyze the connectivity relationship of satellite nodes. The adjacency matrix of the intersatellite link can be expressed as:

[0072] ;

[0073] in, is the total number of satellites in the heterogeneous mega-constellation, Marki Satellites and j The connection status between satellites, if there is an inter-satellite link ISL (Inter-Satellite Link), then ,otherwise, .

[0074] The adjacency matrix can be used to construct a judgment matrix, which can be used to analyze the full connectivity of the giant constellation ISLs. It is called the connectivity judgment matrix and is expressed as:

[0075] ;

[0076] The necessary and sufficient conditions for the constellation to be fully connected are: the matrix All elements in are not 0, and the elements Indicates i Satellite connected to j The number of different paths for the satellites.

[0077] Step 2: Based on the geometric visibility conditions and link pointing change constraints, construct the inter-satellite maximum distance matrix:

[0078] Step 2.1: Assume that each satellite is established l intersatellite links, calculate the maximum distance between any two satellites in the constellation, and obtain the initial matrix of the maximum intersatellite distance :

[0079] ;

[0080] Among them, the matrix Elements in Indicates i Satellite and j The maximum distance between satellites, ;

[0081] ; ;

[0082] in, is the right ascension difference of the ascending nodes of the two satellites; is the phase difference between the two satellites; , are the orbital inclinations of the two satellites respectively; is the radius of the Earth; is the satellite’s orbital altitude;

[0083] Step 2.2: Determine whether any two satellites meet both the geometric visibility condition and the link pointing change constraint condition, and convert the initial matrix The corresponding position elements of two satellites that do not meet the two conditions at the same time are recorded as 0, and the maximum distance matrix between satellites is obtained. .

[0084] Step 3: Based on the inter-satellite maximum distance matrix and the inter-satellite communication connectivity conditions, construct an inter-satellite link connectivity matrix containing the link information between constellation satellites.

[0085] In a specific implementation, an initial adjacency matrix is ​​constructed to characterize whether there is an intersatellite link between satellites; the initial adjacency matrix corresponds to the element position in the intersatellite maximum distance matrix one by one; the first row of the intersatellite maximum distance matrix is ​​used as the current row, and the following assignment and statistical steps are performed: based on the element data of the current row, the initial adjacency matrix is ​​assigned to obtain an intermediate adjacency matrix; the sum of the elements of each row and the sum of the elements of each column in the intermediate adjacency matrix are counted; if the sum of the elements of a row or a column is equal to a specified number, the subsequent assignment and statistical steps of the row or the column are not performed; it is judged whether the sum of the elements of all the current rows and columns reaches the specified number; if not, the next row of the intersatellite maximum distance matrix is ​​re-used as the current row, and the assignment judgment step is continued until the sum of the elements of all the current rows and columns reaches the specified number, and the intermediate adjacency matrix is ​​used as the intersatellite link connectivity matrix containing the link information between the constellation satellites; if yes, the intermediate adjacency matrix is ​​used as the intersatellite link connectivity matrix containing the link information between the constellation satellites; the intersatellite link connectivity matrix determined by the above steps meets the intersatellite communication connectivity conditions.

[0086] Furthermore, the step of assigning values ​​to the initial adjacency matrix based on the element data of the current row to obtain the intermediate adjacency matrix includes: sorting the element data of the current row from small to large, recording the first position of the previously specified number of minimum element data in the inter-star maximum distance matrix; determining the second position corresponding to the first position and the third position symmetrical to the second position in the initial adjacency matrix; and assigning the elements of the second position and the third position both to 1 to obtain the intermediate adjacency matrix.

[0087] The specific steps are as follows:

[0088] Step 3.1: Construct an adjacency matrix to characterize whether there is an ISL between satellites , The initial state is The zero matrix of . Let the loop variable ;

[0089] Step 3.2: From No. i Start with the line i Sort the row data from small to large, and record the first l smallest elements in the matrix The corresponding position in the matrix The corresponding elements in the The symmetric positions in are also assigned a value of 1;

[0090] Step 3.3: Statistics Matrix The sum of each row and column of j The sum of the row elements is denoted by , the sum of the elements in the kth column is recorded as .like or , then, explain j The number of satellites or the kth satellite has reached the upper limit of the link establishment and will no longer be included in the subsequent calculation;

[0091] Step 3.4: If , then continue the cycle, , repeat steps 3.2 and 3.3; otherwise, terminate the loop. Output the final intersatellite link connectivity matrix ;

[0092] Step 3.5: Output the adjacency matrix containing all link information between constellation satellites , that is, the final ISLs design scheme is obtained; that is, the final intersatellite link connectivity matrix It is a matrix including 0 and 1, and the position of 1 represents that two satellites can establish an intersatellite link.

[0093] Step 4: Based on the inter-satellite link connectivity matrix, the end-to-end shortest path transmission SPF protocol is adopted, and the Dijkstra algorithm is used to determine the data transmission path between any two satellites in the constellation.

[0094] The intersatellite link connectivity matrix is ​​divided into a first set including source nodes and a second set including all remaining nodes; the following steps are executed repeatedly until the second set is an empty set: according to the distance information between any two satellites at a certain moment in the weight matrix (the weight matrix is ​​a matrix composed of the distances between any two satellites), the target node with the smallest distance to the source node in the first set is searched, and the target node is added to the first set, and the target node is removed from the second set; it is determined whether the distance between the target node added in the first set and the current source node is less than the current distance value corresponding to the current source node. If so, the distance between the target node and the current source node is applied to update the current distance value corresponding to the current source node in the weight matrix, otherwise it is not updated.

[0095] In specific implementation, the algorithm is based on the intersatellite link design scheme, that is, the adjacency matrix containing information about satellite nodes and edges between nodes is divided into a set S containing source nodes and a set U containing all remaining nodes. According to the distance information between any two satellites at a certain moment in the weight matrix W, search for the node with the smallest distance to the source node and add it to the set S, while removing the node from the set U. Determine whether the distance between the node added in the set S and the source node is less than the current distance value corresponding to the source node. If so, apply the distance between the node and the source node to update the current distance value corresponding to the source node in the weight matrix, otherwise do not update. Repeat the above operation until the set U is an empty set or the intermediate node is the end point E, and the loop ends.

[0096] Step 5: Verify the effectiveness of the method of this embodiment through simulation analysis.

[0097] The orbit altitude is 600km and the orbit inclinations are , based on a hybrid heterogeneous constellation of 5600 satellites, the simulation time is one orbital period, i.e. 96.69 minutes, and the simulation time step is 1 minute. According to the intersatellite link design steps of the present invention, 3, 4, and 5 intersatellite links are respectively carried on each satellite as simulation conditions, and the final design results are obtained as follows Figure 3 shown.

[0098] Figure 3 The subgraphs in each row represent the spatial schematic diagram of each satellite carrying 3, 4, and 5 ISLs. The subgraphs in each column share the same set of source satellite nodes and target satellite nodes, and show the information transmission path. Each satellite has at least l The number of links established on each satellite increases, and the routing selectivity on each satellite node increases, and the communication distance between the two satellites is shortened accordingly. Figure 3 (j), (k), and (l) respectively simulated the changes in the data transmission path distance of three groups of satellite nodes with continuous communication for 600s. The results show that the inter-satellite link design scheme proposed in the present invention can ensure continuous and stable communication between satellites. As the number of on-satellite links increases, the communication distance between two satellites is shortened accordingly, especially when the number of on-satellite links increases from 3 to 4, the communication distance can be greatly shortened. When the number of on-satellite links increases from 4 to 5, the degree of shortening of the communication distance is significantly reduced. Therefore, in actual engineering applications, the technical complexity, construction cost, and communication service quality should be weighed to determine the specific number of on-satellite links. Based on the above analysis, the inter-satellite link design scheme based on a giant heterogeneous constellation proposed in this embodiment can ensure global connectivity and stable and efficient data communication between satellites.

[0099] The beneficial effects of the method provided in this embodiment include but are not limited to:

[0100] (1) The intersatellite link design method provided in this embodiment has the advantage of adapting to the high dynamic changes of low-orbit giant hybrid heterogeneous constellations.

[0101] (2) The intersatellite link design method provided in this embodiment has the advantage of not requiring frequent link reconstruction and relatively stable data transmission.

[0102] (3) The intersatellite link design method provided in this embodiment can ensure that data is transmitted between two satellites using the shortest path.

[0103] Based on the above method embodiment, the present application embodiment also provides an inter-satellite link determination device, see Figure 4 As shown, the device includes: a condition determination module 42, which is used to determine the constraints of the inter-satellite link; the constraints include: geometric visibility conditions, link pointing change constraints and inter-satellite communication connectivity conditions; a first matrix construction module 44, which is used to construct an inter-satellite maximum distance matrix based on the geometric visibility conditions and the link pointing change constraints; each element in the inter-satellite maximum distance matrix represents the maximum distance between two satellites; a second matrix construction module 46, which is used to construct an inter-satellite link connectivity matrix containing link information between constellation satellites based on the inter-satellite maximum distance matrix and the inter-satellite communication connectivity conditions; a transmission path determination module 48, which is used to determine the data transmission path between any two satellites in the constellation based on the inter-satellite link connectivity matrix, using the end-to-end shortest path transmission SPF protocol, and using the Dijkstra algorithm.

[0104] Furthermore, the above-mentioned geometric visibility conditions include:

[0105] ;

[0106] Among them, the vector Respectively represent the position vectors of the two satellites in the ECI coordinate system; h is the distance from the two satellites’ line of sight to the center of the earth; θ It represents the angle between the two satellites and the center of the earth;

[0107] Link pointing change constraints include:

[0108] The constraints on the rotation angle and angular velocity of the intersatellite link are:

[0109] ; ;

[0110] in , They are the maximum azimuth, elevation and low beam rotation angles that the onboard communication equipment can provide. , is the beam rotation angular velocity in the azimuth and elevation directions of the link, and its upper limits are , ; The azimuth of the intersatellite link pointing in the satellite's coordinate system and height angle The calculation formula is:

[0111] ; ; ;

[0112] in, is the direction vector of the coordinate axis of the body coordinate system with the center of mass of satellite m as the origin in the ECI coordinate system, is the direction vector of the intersatellite link between the two satellites, is the link vector in the satellite body coordinate system Projection on a plane; , is the position vector of the satellite in the ECI coordinate system.

[0113] Furthermore, the above intersatellite communication connectivity condition includes: a connectivity judgment matrix, which is expressed as:

[0114] ; ;

[0115] Where A is the adjacency matrix; Indicates i Satellites and j The connection status between satellites. If there is an intersatellite link, ,otherwise, ; is the total number of satellites in the heterogeneous mega-constellation;

[0116] The necessary and sufficient conditions for the constellation to be fully connected are: the matrix All elements in are not 0, and the elements Indicates i Satellite connected to j The number of different paths for the satellites.

[0117] Furthermore, the first matrix construction module 44 is used to assume that multiple inter-satellite links are established on each satellite, calculate the maximum distance between any two satellites in the constellation, and obtain the inter-satellite maximum distance initial matrix :

[0118] ;

[0119] in, ;

[0120] ; ;

[0121] in, is the right ascension difference of the ascending nodes of the two satellites; is the phase difference between the two satellites; , are the orbital inclinations of the two satellites respectively; is the radius of the Earth; is the satellite’s orbital altitude;

[0122] Determine whether any two satellites meet the geometric visibility conditions and link pointing change constraints at the same time, and convert the initial matrix The corresponding position elements of two satellites that do not meet the two conditions at the same time are recorded as 0, and the maximum distance matrix between satellites is obtained. .

[0123] Further, the second matrix construction module 46 is used to construct an initial adjacency matrix that characterizes whether there are inter-satellite links between satellites; the initial adjacency matrix corresponds to the element positions in the inter-satellite maximum distance matrix one by one; the first row of the inter-satellite maximum distance matrix is ​​used as the current row, and the following assignment and statistical steps are performed: based on the element data of the current row, the initial adjacency matrix is ​​assigned to obtain an intermediate adjacency matrix; the sum of the elements of each row and the sum of the elements of each column in the intermediate adjacency matrix are counted; if the sum of the elements of a row or a column is equal to the specified number, the subsequent assignment and statistical steps of the row or column are not performed; it is determined whether the sum of the elements of all current rows and columns reaches the specified number; if not, the next row of the inter-satellite maximum distance matrix is ​​used as the current row again, and the assignment judgment step is continued until the sum of the elements of all current rows and columns reaches the specified number, and the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; if yes, the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; the inter-satellite link connectivity matrix meets the inter-satellite communication connectivity conditions.

[0124] Furthermore, the second matrix construction module 46 is used to sort the element data of the current row from small to large, record the first position of the previously specified number of minimum element data in the inter-satellite maximum distance matrix; determine the second position corresponding to the first position in the initial adjacency matrix, and the third position symmetrical to the second position; assign the elements of the second position and the third position to 1, and obtain the intermediate adjacency matrix.

[0125] Furthermore, the transmission path determination module 48 is used to divide the intersatellite link connectivity matrix into a first set including source nodes and a second set including all remaining nodes; the following steps are executed in a loop until the second set is an empty set: according to the distance information between any two satellites at a certain moment in the weight matrix, the target node with the smallest distance to the source node in the first set is searched, and the target node is added to the first set, and the target node is removed from the second set; the weight matrix is ​​a matrix composed of the distances between any two satellites; it is determined whether the distance between the target node added in the first set and the current source node is less than the current distance value corresponding to the current source node, and if so, the distance between the target node and the current source node is applied to update the current distance value corresponding to the current source node in the weight matrix, otherwise it is not updated.

[0126] The device provided in the embodiment of the present application has the same implementation principle and technical effects as those of the aforementioned method embodiment. For the sake of brief description, for matters not mentioned in the embodiment of the device, reference may be made to the corresponding contents in the aforementioned method embodiment.

[0127] The present application also provides an electronic device, such as Figure 5 As shown, it is a schematic diagram of the structure of the electronic device, wherein the electronic device includes a processor 51 and a memory 50, the memory 50 stores computer executable instructions that can be executed by the processor 51, and the processor 51 executes the computer executable instructions to implement the above method.

[0128] exist Figure 5 In the illustrated embodiment, the electronic device further includes a bus 52 and a communication interface 53 , wherein the processor 51 , the communication interface 53 and the memory 50 are connected via the bus 52 .

[0129] Among them, the memory 50 may include a high-speed random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 53 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. can be used. The bus 52 can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus 52 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 5 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0130] The processor 51 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 51. The above processor 51 can be a general processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The general processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to execute, or the hardware and software modules in the decoding processor are combined and executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor 51 reads the information in the memory and completes the steps of the method of the above embodiment in combination with its hardware.

[0131] An embodiment of the present application also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the above method. The specific implementation can be found in the aforementioned method embodiment, which will not be repeated here.

[0132] The computer program products of the methods, devices, and electronic devices provided in the embodiments of the present application include a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the previous method embodiments. The specific implementation can be found in the method embodiments, which will not be repeated here.

[0133] Unless otherwise specifically stated, the relative steps, numerical expressions and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0134] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0135] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0136] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for determining an intersatellite link, characterized in that: The method comprises: Determining constraints of the intersatellite link; the constraints include: geometric visibility conditions, link pointing change constraints and intersatellite communication connectivity conditions; Based on the geometric visibility conditions and the link pointing change constraint conditions, constructing an inter-satellite maximum distance matrix; each element in the inter-satellite maximum distance matrix represents the maximum distance between two satellites; Based on the inter-satellite maximum distance matrix and the inter-satellite communication connectivity condition, an inter-satellite link connectivity matrix including link information between constellation satellites is constructed, including: constructing an initial adjacency matrix characterizing whether there is an inter-satellite link between satellites; the initial adjacency matrix corresponds to the element position in the inter-satellite maximum distance matrix one by one; taking the first row of the inter-satellite maximum distance matrix as the current row, performing the following assignment and statistical steps: assigning values ​​to the initial adjacency matrix based on the element data of the current row to obtain an intermediate adjacency matrix; counting the sum of the elements in each row and the sum of the elements in each column in the intermediate adjacency matrix; if the sum of the elements in a row or the sum of the elements in a column is equal, If the number of elements in all rows and columns reaches the specified number, the subsequent assignment and statistical step of the row or column is not performed; it is determined whether the sum of the elements in all the current rows and columns reaches the specified number; if not, the next row of the inter-satellite maximum distance matrix is ​​used as the current row again, and the assignment and judgment step is continued until the sum of the elements in all the current rows and columns reaches the specified number, and the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; if yes, the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; the inter-satellite link connectivity matrix meets the inter-satellite communication connectivity condition; Based on the intersatellite link connectivity matrix, the end-to-end shortest path transmission SPF protocol is adopted, and the Dijkstra algorithm is used to determine the data transmission path between any two satellites in the constellation.

2. The method according to claim 1, characterized in that The geometric visibility conditions include: ； Among them, the vector Respectively represent the position vectors of the two satellites in the ECI coordinate system; h is the distance from the two satellites’ line of sight to the center of the earth; θ It represents the angle between the two satellites and the center of the earth; The link orientation change constraint condition includes: The constraints on the rotation angle and angular velocity of the intersatellite link are: ； ； in , They are the maximum azimuth, elevation and low beam rotation angles that the onboard communication equipment can provide. , is the beam rotation angular velocity in the azimuth and elevation directions of the link, and its upper limits are , ; The azimuth of the intersatellite link pointing in the satellite's coordinate system and height angle The calculation formula is: ； ； ； in, is the direction vector of the coordinate axis of the body coordinate system with the center of mass of satellite m as the origin in the ECI coordinate system, is the direction vector of the intersatellite link between the two satellites, is the link vector in the satellite body coordinate system Projection on a plane; , is the position vector of the satellite in the ECI coordinate system.

3. The method according to claim 1, characterized in that The intersatellite communication connectivity condition includes: a connectivity judgment matrix, which is expressed as: ； ； Where A is the adjacency matrix; Indicates i Satellites and j The connection status between satellites. If there is an intersatellite link, ,otherwise, ; is the total number of satellites in the heterogeneous mega-constellation; The necessary and sufficient conditions for the constellation to be fully connected are: the matrix All elements in are not 0, and the elements Indicates i Satellite connected to j The number of different paths for the satellites.

4. The method according to claim 1, characterized in that: The step of constructing an inter-satellite maximum distance matrix based on the geometric visibility condition and the link pointing change constraint condition comprises: Assuming that multiple intersatellite links are established on each satellite, the maximum distance between any two satellites in the constellation is calculated to obtain the initial matrix of the maximum intersatellite distance: : ； in, ; ； ； in, is the right ascension difference of the ascending nodes of the two satellites; is the phase difference between the two satellites; , are the orbital inclinations of the two satellites respectively; is the radius of the Earth; is the satellite’s orbital altitude; Determine whether any two satellites meet the geometric visibility condition and the link pointing change constraint condition at the same time, and convert the initial matrix The corresponding position elements of two satellites that do not meet the two conditions at the same time are recorded as 0, and the maximum distance matrix between satellites is obtained. .

5. The method according to claim 1, characterized in that The step of assigning values ​​to the initial adjacency matrix based on the element data of the current row to obtain an intermediate adjacency matrix comprises: Sort the element data of the current row from small to large, and record the first position of the previously specified number of smallest element data in the inter-satellite maximum distance matrix; Determine a second position corresponding to the first position and a third position symmetrical to the second position in the initial adjacency matrix; The elements at the second position and the third position are both assigned a value of 1 to obtain an intermediate adjacency matrix.

6. The method according to claim 1, characterized in that Based on the intersatellite link connectivity matrix, the step of using the end-to-end shortest path transmission SPF protocol and using the Dijkstra algorithm to determine the data transmission path between any two satellites in the constellation includes: Divide the intersatellite link connectivity matrix into a first set including source nodes and a second set including all remaining nodes; loop through the following steps until the second set is an empty set: According to the distance information between any two satellites at a certain moment in the weight matrix, search for the target node with the smallest distance to the current source node in the first set, and add the target node to the first set, while removing the target node from the second set; the weight matrix is ​​a matrix composed of the distance values ​​between any two satellites; Determine whether the distance between the target node added in the first set and the current source node is less than the current distance value corresponding to the current source node. If so, apply the distance between the target node and the current source node to update the current distance value corresponding to the current source node in the weight matrix, otherwise do not update.

7. An inter-satellite link determination device suitable for low-orbit hybrid heterogeneous giant constellation, characterized in that: The device comprises: A condition determination module is used to determine the constraints of the intersatellite link; the constraints include: geometric visibility conditions, link pointing change constraints and intersatellite communication connectivity conditions; A first matrix construction module is used to construct an inter-satellite maximum distance matrix based on the geometric visibility condition and the link pointing change constraint condition; each element in the inter-satellite maximum distance matrix represents the maximum distance between two satellites; The second matrix construction module is used to construct an intersatellite link connectivity matrix containing link information between constellation satellites based on the intersatellite maximum distance matrix and the intersatellite communication connectivity conditions, including: constructing an initial adjacency matrix that characterizes whether there is an intersatellite link between satellites; the initial adjacency matrix corresponds to the element position in the intersatellite maximum distance matrix one by one; taking the first row of the intersatellite maximum distance matrix as the current row, and performing the following assignment and statistical steps: assigning values ​​to the initial adjacency matrix based on the element data of the current row to obtain an intermediate adjacency matrix; counting the sum of the elements of each row and the sum of the elements of each column in the intermediate adjacency matrix; if the sum of the elements of a row or a column is If the sum of the column elements is equal to the specified number, the subsequent assignment and statistical step of the row or column is not performed; it is judged whether the sum of the elements of all the current rows and columns reaches the specified number; if not, the next row of the inter-satellite maximum distance matrix is ​​used as the current row again, and the assignment judgment step is continued until the sum of the elements of all the current rows and columns reaches the specified number, and the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; if yes, the intermediate adjacency matrix is ​​used as the inter-satellite link connectivity matrix containing the link information between the constellation satellites; the inter-satellite link connectivity matrix meets the inter-satellite communication connectivity condition; The transmission path determination module is used to determine the data transmission path between any two satellites in the constellation based on the inter-satellite link connectivity matrix, using the end-to-end shortest path transmission SPF protocol and the Dijkstra algorithm.

8. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer executable instructions that can be executed by the processor, and the processor executes the computer executable instructions to implement the method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the method according to any one of claims 1 to 6.

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