Satellite-ground access method and system for low-orbit satellite network

Abstract

The embodiment of the invention provides a satellite-ground access method and system for a low-orbit satellite network, and belongs to the technical field of satellite communication. The method comprises the following steps: determining a user to be accessed to a satellite; dividing users to be accessed to the satellite into high-priority users and low-priority users; determining gateway satellites of the high-priority users according to inter-satellite routing hops; determining the gateway satellites of the low-priority users according to the average access user number of each gateway satellite; determining access satellites of the high-priority users according to the access time of each high-priority user, the inter-satellite routing hop count and the current elevation angle; and determining the access satellites of the low-priority users according to the elevation angle of each low-priority user and the number of available channels of the access satellites in the visual range. According to the method and the system, the gateway satellites and the access satellites are efficiently scheduled, so that the requirements of time delay and signal strength of low-orbit satellite communication are met.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and particularly to a method and system for satellite-ground access in a low-earth orbit satellite network. Background Art

[0002] Low-earth orbit satellite communication is one of the important ways of modern outdoor wireless communication. At present, a low-earth orbit satellite network generally includes hundreds to tens of thousands of LEO (Low Earth Orbit) satellites. Each ground user is usually covered by multiple low-earth orbit satellites at the same time, but only establishes a communication link with one low-earth orbit satellite at a time. The satellites in the constellation move at high speeds and the network topology changes frequently. The single coverage time of a satellite is only a few minutes, and the satellite-ground link switches frequently. Generally, the destination node of user data transmission is determined, and user data is transmitted along the process of "user terminal - access satellite - relay satellite - gateway satellite - gateway station - ground network - destination node". The user terminal selects different access satellites and reaches the gateway station along different inter-satellite routes, resulting in huge differences in terms of the number of routing hops and network load, seriously affecting the signal transmission quality and delay.

[0003] In the prior art, there is a lack of an efficient scheduling algorithm for the selection of gateway satellites and access satellites. A low-earth orbit giant satellite network has characteristics such as high topological dynamicity, limited on-board computing and storage capabilities, and uneven ground traffic distribution, which may cause problems such as high transmission delay, network congestion, and link interruption. Establishing a stable, efficient, and balanced satellite communication link can effectively alleviate the above problems. A satellite communication link includes a satellite-ground link and an inter-satellite link. The satellite-ground access strategy is how a ground terminal selects an access satellite to establish a satellite-ground link. The satellites in the constellation move at high speeds and the network topology changes frequently. A user terminal is usually covered by multiple satellites at the same time, and the single coverage time of a satellite is only a few minutes. Selecting an inappropriate access satellite will not only cause frequent switching of the satellite-ground link, but also bring significant differences in the inter-satellite routing, greatly increasing the inter-satellite routing cost. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a method and system for satellite-ground access in a low-earth orbit satellite network. The method and system can meet the requirements of delay and signal strength in low-earth orbit satellite communication by efficiently scheduling gateway satellites and access satellites.

[0005] To achieve the above purpose, the embodiments of the present invention provide a method for satellite-ground access in a low-earth orbit satellite network, including:

[0006] Determine the users of the satellite to be accessed;

[0007] Divide the users of the satellite to be accessed into high-priority users and low-priority users;

[0008] Determine the gateway satellite of the high-priority user according to the number of inter-satellite routing hops;

[0009] Determine the gateway satellite of the low-priority user according to the average number of access users of each gateway satellite;

[0010] Determine the access satellite of the high-priority user according to the access time, the number of inter-satellite routing hops, and the current elevation angle of each high-priority user;

[0011] Determine the access satellite of the low-priority user according to the elevation angle of each low-priority user and the number of available channels of the access satellites within the visible range.

[0012] Optionally, the method further includes:

[0013] Determine the currently unavailable satellites;

[0014] Update the penalty factor and the number of inter-satellite routing hops according to the number of the unavailable satellites.

[0015] Optionally, dividing the users to be accessed to satellites into high-priority users and low-priority users includes:

[0016] Judge whether the user is sensitive to delay;

[0017] In the case of judging that the user is sensitive to delay, divide the user into a high-priority user;

[0018] In the case of judging that the user is not sensitive to delay, divide the user into a low-priority user.

[0019] Optionally, updating the penalty factor and the number of inter-satellite routing hops according to the number of the unavailable satellites includes:

[0020] Update the penalty factor and the number of inter-satellite routing hops according to formulas (1) to (5):

[0021] α = N overload / N total , (1)

[0022] where α is the penalty factor, N overload is the number of satellites whose load in the path exceeds a preset threshold, and N total is the total number of satellites in the path;

[0023]

[0024] where, is the updated number of inter-satellite routing hops between user q and gateway station j in the A2A orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the A2A orbit mode before update;

[0025]

[0026] Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated A2D orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the A2D orbit mode before update;

[0027]

[0028] Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated D2A orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the D2A orbit mode before update;

[0029]

[0030] Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated D2D orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the D2D orbit mode before update.

[0031] Optionally, determining the gateway satellite of the high-priority user according to the number of inter-satellite routing hops includes:

[0032] Determining the gateway satellite of the high-priority user according to the following formulas (6) and (7):

[0033]

[0034] s.t.N p ≤N max , p ∈ [1, P], (7)

[0035] Among them, H q is the number of inter-satellite routing hops of the terminal q of the high-priority user, Q is the set of high-priority users, N p is the maximum number of access users of the gateway satellite p, N max is the maximum number of access users of each gateway satellite, and P is the set of gateway satellites.

[0036] Optionally, determining the gateway satellite of the low-priority user according to the average number of access users of each gateway satellite includes:

[0037] Determining the gateway satellite of the low-priority user according to the following formulas (8) to (10):

[0038]

[0039] such that N p ≤N max , p ∈ [1, P], (9)

[0040]

[0041] wherein, N p is the maximum number of access users of gateway satellite p, is the average number of access users of the gateway satellite, N max is the maximum number of access users of each gateway satellite, and P is the set of gateway satellites.

[0042] Optionally, determining the access satellite for each high-priority user according to the access time, the number of inter-satellite routing hops, and the current elevation angle includes:

[0043] Determining the objective function of the access satellite for the high-priority user according to the following formula (11):

[0044]

[0045] wherein, O m is the objective function of the m-th access satellite for the high-priority user, T max is the maximum value of the access time of the access satellite, T min is the minimum value of the access time of the access satellite, T m is the available remaining time of the access satellite, ω1 is the weight of the access time, ω2 is the weight of the number of inter-satellite routing hops of the gateway satellite, H m is the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, H min is the minimum value of the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, H max is the maximum value of the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, ω3 is the weight of the elevation angle, EL m is the elevation angle of the access satellite, EL min is the minimum value of the elevation angle of the access satellite, EL max is the maximum value of the elevation angle of the access satellite;

[0046] Select the access satellite with the maximum objective function to access the terminal of the high-priority user.

[0047] Optionally, determining the access satellite for each low-priority user according to the elevation angle of the low-priority user and the available number of channels of the access satellites within the visible range includes:

[0048] The objective function value of the access satellite for each of the low-priority users is calculated using the following formula (12):

[0049]

[0050] where O m ′ is the objective function of the m-th access satellite for the low-priority user, ω4 is the weight of the number of available channels, CH m is the number of available channels of the m-th access satellite, CH min is the minimum value of the number of available channels of the access satellite, CH max is the maximum value of the number of available channels of the access satellite, ω5 is the weight of the elevation angle of the access satellite for the low-priority user, EL m is the elevation angle of the access satellite, EL min is the minimum value of the elevation angle of the access satellite, EL max is the maximum value of the elevation angle of the access satellite;

[0051] Select the access satellite with the maximum objective function value to access the terminal of the low-priority user.

[0052] On the other hand, the present invention also provides a space-ground access system for a low-Earth orbit satellite network. The access system includes a processor configured to execute the method described in any of the above.

[0053] On yet another aspect, the present invention also provides a computer-readable storage medium storing a program for being read by a machine to cause the machine to execute the method described in any of the above.

[0054] Through the above technical solutions, the embodiments of the present invention provide a space-ground access method and system for a low-Earth orbit satellite network. By dividing users into high-priority users and low-priority users, and respectively using different metrics to determine the gateway satellite and access satellite for users with different priorities, efficient satellite scheduling is achieved while meeting the communication requirements of users, and the scheduling efficiency of satellites in low-Earth orbit satellite communication is improved.

[0055] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification, and are used together with the following specific implementation to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0057] Figure 1It is a flowchart of a space - to - ground access method for a low - earth - orbit satellite network according to an embodiment of the present invention. Detailed implementation manners

[0058] The following will explain in detail the specific implementation manners of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for explaining and interpreting the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0059] In the embodiments of the present application, some industry - existing solutions such as certain software, components, models, etc. may be mentioned. They should be regarded as exemplary. The purpose is only to illustrate the feasibility in the implementation of the technical solutions of the present application, but it does not mean that the applicant has already or necessarily used this solution.

[0060] As Figure 1 shown is a flowchart of a space - to - ground access method for a low - earth - orbit satellite network according to an embodiment of the present invention. In this Figure 1 method, the method may include the following steps:

[0061] In step S10, determine the users to access the satellite;

[0062] In step S11, divide the users to access the satellite into high - priority users and low - priority users;

[0063] In step S12, determine the gateway satellite for high - priority users according to the number of inter - satellite routing hops;

[0064] In step S13, determine the gateway satellite for low - priority users according to the average number of access users of each gateway satellite;

[0065] In step S14, determine the access satellite for high - priority users according to the access time, the number of inter - satellite routing hops, and the current elevation angle of each high - priority user;

[0066] In step S15, determine the access satellite for low - priority users according to the elevation angle of each low - priority user and the available channel numbers of the access satellites within the visible range.

[0067] In the method shown as Figure 1 above, step S10 can be used to determine the users to access the satellite. Specifically, the users can be obtained directly by reading the user list stored in the network management center.

[0068] Step S11 can be used to divide the users to be connected to the satellite into high-priority users and low-priority users. Among them, the specific basis for dividing the high-priority users and low-priority users can be various forms known to those skilled in the art, including but not limited to the payment level, communication quality requirements, etc. In an example of the present invention, the method for dividing the high-priority users and low-priority users can be to first determine whether the user is sensitive to latency. If it is determined that the user is sensitive to latency, the user is divided into high-priority users; conversely, if it is determined that the user is not sensitive to latency, the user can be divided into low-priority users. As for the specific method for determining whether it is sensitive to latency, it can be various forms known to those skilled in the art. In an example of the present invention, it can be to determine whether the latency value of the user is greater than or equal to a preset threshold; if it is determined that the latency value is greater than or equal to the threshold, it is determined that the user is not sensitive to latency. Conversely, if it is determined that the latency value is less than the threshold, it is determined that the user is sensitive to latency.

[0069] Step S12 can be used to determine the gateway satellite of high-priority users according to the number of inter-satellite routing hops. The method for obtaining the number of inter-satellite routing hops can be to first map the user's terminal and the gateway station to the satellites at the zenith respectively, and then determine the routing hops between the two mapped satellites, so as to obtain the number of inter-satellite routing hops. Specifically, in this embodiment, to obtain the number of inter-satellite routing hops, it is first necessary to calculate the right ascension of the ascending node and the in-orbit phase of the satellite mapped by the user's terminal by using the following formulas (1) and (2):

[0070]

[0071] Ω1 = Lon - arctan(cosφtanθ1), (2)

[0072] where, θ1 is the in-orbit phase, Lat is the longitude of the user's terminal, φ is the orbital inclination angle, Lon is the latitude of the user's terminal, and Ω1 is the right ascension of the ascending node.

[0073] Similarly, the right ascension of the ascending node Ω2 and the in-orbit phase θ2 of the gateway station can also be calculated by using the above formulas (1) and (2).

[0074] Then, use the following formulas (3) to (5) to calculate the routing hops (horizontal hops) across the orbit, the routing hops (vertical hops) within the orbit, and the total hops between the user's terminal and the gateway station:

[0075]

[0076] H = |H h | + |H v |, (5)

[0077] Among them, H h is the routing hop count across orbits, ΔΩ is the angular difference between adjacent orbital planes, Roound is the rounding function, and H v is the routing hop count within the orbit, Δf is the phase difference between adjacent orbital satellites caused by the phase factor, and H is the total hop count.

[0078] Considering that there are four orbital modes for satellites in the prior art, namely: A2A, A2D, D2A, and D2D, when calculating the inter-satellite routing hop count, these four orbital modes need to be considered. Therefore, the inter-satellite routing hop count can be calculated using the following formulas (6) and (7):

[0079]

[0080] Among them, is the estimated hop count (inter-satellite routing hop count) from user terminal q to the ascending-orbit gateway satellite of gateway station j, is the estimated hop count (inter-satellite routing hop count) from user terminal q to the descending-orbit gateway satellite of gateway station j, is the total hop count in the A2A mode, is the total hop count in the D2A mode, is the total hop count in the A2D mode, is the total hop count in the D2D mode.

[0081] In addition, in step S12, considering that some factors of the satellite may cause it to be currently unavailable, thus affecting the calculation of the inter-satellite routing hop count. In one embodiment of the present invention, the method may further include a step of updating the inter-satellite routing hop count. Specifically, in this embodiment, step S12 may first determine the currently unavailable satellites, and then update the penalty factor and the inter-satellite routing hop count according to the number of the unavailable satellites. Among them, for the specific methods of updating the penalty factor and the inter-satellite routing hop count, there may be various forms known to those skilled in the art. In one example of the present invention, the penalty factor and the inter-satellite routing hop count may be updated according to the following formulas (8) to (12):

[0082] α = N overload / N total , (8)

[0083] Among them, α is the penalty factor, and N overload is the number of satellites whose load in the path exceeds the preset threshold, and N total is the total number of satellites in the path;

[0084]

[0085] Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated A2A orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the A2A orbit mode before update;

[0086]

[0087] wherein, is the number of inter-satellite routing hops between user q and gateway station j in the updated A2D orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the A2D orbit mode before update;

[0088]

[0089] wherein, is the number of inter-satellite routing hops between user q and gateway station j in the updated D2A orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the D2A orbit mode before update;

[0090]

[0091] wherein, is the number of inter-satellite routing hops between user q and gateway station j in the updated D2D orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the D2D orbit mode before update.

[0092] After determining the number of inter-satellite routing hops, step S12 can continue to determine the gateway satellite of the high-priority user. Specifically, in this embodiment, the following formulas (13) and (14) can be used to determine the gateway satellite of the high-priority user:

[0093]

[0094] s.t.N p ≤N max ,p∈[1,P], (14)

[0095] wherein, H q is the number of inter-satellite routing hops of the terminal q of the high-priority user, Q is the set of high-priority users, N p is the maximum number of access users of gateway satellite p, N max is the maximum number of access users of each gateway satellite, and P is the set of gateway satellites.

[0096] Step S13 can be used to determine the gateway satellite for low-priority users according to the average number of access users of each gateway satellite. Specifically, in this embodiment, the gateway satellite for the low-priority users can be determined by using the following formulas (13) to (15):

[0097]

[0098] s.t.N p ≤N max , p ∈ [1, P], (14)

[0099]

[0100] Wherein, N p is the maximum number of access users of gateway satellite p, is the average number of access users of gateway satellite, N max is the maximum number of access users of each gateway satellite, and P is the set of gateway satellites.

[0101] Step S14 can be used to determine the access satellite for high-priority users according to the access time, the number of inter-satellite routing hops, and the current elevation angle of each high-priority user. Specifically, in this embodiment, the following formula (16) can be used as the objective function for the access satellite of high-priority users:

[0102]

[0103] Wherein, O m is the objective function of the m-th access satellite for high-priority users, T max is the maximum value of the access time of the access satellite, T min is the minimum value of the access time of the access satellite, T m is the available remaining time of the access satellite, ω1 is the weight of the access time, ω2 is the weight of the number of inter-satellite routing hops of the gateway satellite, H m is the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, H min is the minimum value of the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, H max is the maximum value of the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, ω3 is the weight of the elevation angle, EL m is the elevation angle of the access satellite, EL min is the minimum value of the elevation angle of the access satellite, EL max is the maximum value of the elevation angle of the access satellite. Then, for the objective function value of each calculated access satellite, the access satellite with the largest objective function value is selected as the final access satellite.

[0104] Step S15 can be used to determine the access satellite for each low-priority user according to the elevation angle of each low-priority user and the number of available channels of the access satellites within the visible range. Specifically, in this embodiment, this step S15 may first calculate the objective function of the access satellite for each low-priority user through the following formula (17):

[0105]

[0106] wherein, O m ′ is the objective function of the m-th access satellite for the low-priority user, ω4 is the weight of the number of available channels, CH m is the number of available channels of the m-th access satellite, CH min is the minimum value of the number of available channels of the access satellite, CH max is the maximum value of the number of available channels of the access satellite, ω5 is the weight of the elevation angle of the access satellite for the low-priority user, EL m is the elevation angle of the access satellite, EL min is the minimum value of the elevation angle of the access satellite, EL max is the maximum value of the elevation angle of the access satellite. Then, select the access satellite with the largest objective function value to access the terminal of the low-priority user.

[0107] On the other hand, the present invention also provides a space-ground access system for a low-earth orbit satellite network, and the access system includes a processor configured to execute the method as described in any one of the above.

[0108] On yet another aspect, the present invention also provides a computer-readable storage medium storing a program for being read by a machine to cause the machine to execute the method as described in any one of the above.

[0109] Through the above technical solutions, the embodiments of the present invention provide a space-ground access method and system for a low-earth orbit satellite network. By dividing users into high-priority users and low-priority users, and respectively using different metrics to determine the gateway satellite and the access satellite for users with different priorities, high-efficiency satellite scheduling is achieved while meeting the communication requirements of users, and the scheduling efficiency of satellites in low-earth orbit satellite communication is improved.

[0110] Those skilled in the art should understand that the embodiments of the present application may be provided as a method, a system, or a computer program product. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0111] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices produce means for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0112] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including instruction means that implement the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0113] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0114] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and a memory.

[0115] The memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM), and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. The memory is an example of computer-readable media.

[0116] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are 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, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0117] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0118] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A satellite-ground access method for a low-earth orbit satellite network, characterized in that, The method includes: Determine the users to access the satellite; Divide the users to access the satellite into high-priority users and low-priority users; Determine the gateway satellite of the high-priority users according to the number of inter-satellite routing hops; Determine the gateway satellite of the low-priority users according to the average number of access users of each gateway satellite; Determine the access satellite of the high-priority users according to the access time, the number of inter-satellite routing hops, and the current elevation angle of each high-priority user; Determine the access satellite of the low-priority users according to the elevation angle of each low-priority user and the available channel numbers of the access satellites within the visible range.

2. The method according to claim 1, wherein The method further includes: Determine the currently unavailable satellites; Update the penalty factor and the number of inter-satellite routing hops according to the number of the unavailable satellites.

3. The method according to claim 1, characterized in that Dividing the users to access the satellite into high-priority users and low-priority users includes: Judge whether the user is sensitive to latency; In the case of judging that the user is sensitive to latency, divide the user into high-priority users; In the case of judging that the user is not sensitive to latency, divide the user into low-priority users.

4. The method according to claim 2, wherein Updating the penalty factor and the number of inter-satellite routing hops according to the number of the unavailable satellites includes: Update the penalty factor and the number of inter-satellite routing hops according to formulas (1) to (5): α = N overload / N total , (1) where α is the penalty factor, N overload is the number of satellites whose load in the path exceeds a preset threshold value, and N total is the total number of satellites in the path; Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated A2A orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the A2A orbit mode before update; Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated A2D orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the A2D orbit mode before update; Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated D2A orbit mode, is the number of inter-satellite routing hops between user q and gateway station j in the D2A orbit mode before update; Among them, is the number of inter-satellite routing hops between user q and gateway station j in the updated D2D orbit mode. is the number of inter-satellite routing hops between user q and gateway station j in the D2D orbit mode before update.

5. The method according to claim 1, wherein Determining the gateway satellite of the high-priority users according to the number of inter-satellite routing hops includes: Determine the gateway satellite of the high-priority users according to the following formulas (6) and (7): such that N p ≤B max , p ∈ [1, P], (7) Among them, H q is the inter-satellite routing hop count of the terminal q of high-priority users, Q is the set of high-priority users, N p is the maximum number of users that can access the gateway satellite p, N max is the maximum number of users that can access each gateway satellite, and P is the set of gateway satellites.

6. The method according to claim 1, wherein Determining the gateway satellite of the low-priority users according to the average number of access users of each gateway satellite includes: Determine the gateway satellite of the low-priority users according to the following formulas (8) to (10): s.t.N p ≤N max ,p∈[1,P], (9) Among them, N p is the maximum number of access users of gateway satellite p, is the average number of access users of the gateway satellite, N max is the maximum number of access users of each gateway satellite, and P is the set of gateway satellites.

7. The method according to claim 1, characterized in that, Determining the access satellite of the high-priority users according to the access time, the number of inter-satellite routing hops, and the current elevation angle of each high-priority user includes: Determine the objective function of the access satellite of the high-priority users according to the following formula (11): Among them, O m is the objective function of the m-th access satellite of the high-priority user, T max is the maximum value of the access time of the access satellite, T min is the minimum value of the access time of the access satellite, T m is the available remaining time of the access satellite, ω1 is the weight of the access time, ω2 is the weight of the number of inter-satellite routing hops of the gateway satellite, H m is the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, H min is the minimum value of the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, H max is the maximum value of the number of inter-satellite routing hops from the terminal of the current high-priority user to the access satellite, ω3 is the weight of the elevation angle, EL m is the elevation angle of the access satellite, EL min is the minimum value of the elevation angle of the access satellite, EL max is the maximum value of the elevation angle of the access satellite; Select the access satellite with the maximum objective function to access the terminal of the high-priority users.

8. The method according to claim 1, characterized in that, Determining the access satellite of the low-priority users according to the elevation angle of each low-priority user and the available channel numbers of the access satellites within the visible range includes: Calculate the objective function value of the access satellite of each low-priority user by using the following formula (12): Among them, O m ′ is the objective function of the m-th access satellite of the low-priority user, ω4 is the weight of the number of available channels, CH m is the number of available channels of the m-th access satellite, CH min is the minimum value of the number of available channels of the access satellite, CH max is the maximum value of the number of available channels of the access satellite, ω5 is the weight of the elevation angle of the access satellite of the low-priority user, EL m is the elevation angle of the access satellite, EL min is the minimum value of the elevation angle of the access satellite, EL max is the maximum value of the elevation angle of the access satellite; Select the access satellite with the maximum objective function value to access the terminal of the low-priority users.

9. A satellite-ground access system for a low-earth orbit satellite network, characterized in that, The access system includes a processor, and the processor is configured to execute the method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program, and the program is used to be read by a machine so that the machine executes the method according to any one of claims 1 to 8.

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