Method for realizing inter-satellite beam switching of low-orbit satellite communication terminal and medium

Abstract

The invention discloses a method for realizing inter-satellite beam switching of a low-orbit satellite communication terminal and a medium, and belongs to the technical field of low-orbit satellite communication, and the method comprises the steps: tracking a target satellite based on an obtained initial ephemeris, and receiving a satellite signal of the target satellite; receiving a low earth orbit satellite ephemeris sent by the low earth orbit satellite communication system and updating the ephemeris; and based on the residual service time of the target satellite and the signal-to-noise ratio of the satellite signal, judging whether to perform inter-satellite beam switching, if so, performing inter-satellite beam switching based on the ephemeris of the low-orbit satellite, and if not, continuing to perform satellite tracking based on the initial ephemeris so as to solve the problem existing in the inter-satellite beam switching process and improve the satellite tracking efficiency. And the problem of data link instability or communication interruption is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-orbit satellite communications, and in particular relates to a method and medium for implementing inter-satellite beam switching of a low-orbit satellite communication terminal. Background Art

[0002] Low-orbit satellite communication systems are developing faster and faster in the field of satellite communication by virtue of their advantages such as high network speed and low latency. my country is also vigorously developing low-orbit satellite communication systems. Low-orbit satellite communication terminals are the entrances for ground users to access low-orbit satellite communication systems, and are used to establish stable data transmission links with satellites. Since low-orbit communication satellites orbit the earth at a fast speed and have a short overhead time, generally more than 10 minutes, ground communication terminals need to point the antenna beam of the terminal to the communication satellite at all times to achieve long-term stable communication. This requires that the antenna beam be switched to an available satellite in time when the current satellite channel fades to ensure that the data link between the terminal and the satellite is always connected. The above is inter-satellite beam switching. If there are problems in the inter-satellite beam switching process, the data link may become unstable at the least, and the communication may be directly interrupted at the worst. In order to solve the above problems, the present invention designs a method and medium for implementing inter-satellite beam switching by a low-orbit satellite communication terminal (hereinafter referred to as: satellite communication terminal). Summary of the invention

[0003] The purpose of the present invention is to provide a method and medium for implementing inter-satellite beam switching of a low-orbit satellite communication terminal, so as to solve the problem of data link instability or communication interruption caused by problems in the inter-satellite beam switching process.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] On the one hand, this specification provides a method for implementing inter-satellite beam switching of a low-orbit satellite communication terminal, including:

[0006] Step 102, tracking the target satellite based on the acquired initial ephemeris, and receiving the satellite signal of the target satellite;

[0007] Step 104, receiving the low-orbit satellite ephemeris sent by the low-orbit satellite communication system and updating the ephemeris;

[0008] Step 106, based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal, determine whether to perform inter-satellite beam switching. If yes, perform inter-satellite beam switching based on the low-orbit satellite ephemeris. If no, continue to track the satellite based on the initial ephemeris.

[0009] On the other hand, the present specification provides a medium for a low-orbit satellite communication terminal to perform inter-satellite beam switching, including:

[0010] A communication baseband, used to control the antenna to track the target satellite based on the acquired initial ephemeris, receive and process the satellite signal of the target satellite, and receive the low-orbit satellite ephemeris sent by the low-orbit satellite communication system;

[0011] Combined inertial navigation, used to obtain the position and attitude information of satellite communication terminals;

[0012] A control processing chip, used to control the antenna;

[0013] A computing and processing chip, used to determine whether to perform inter-satellite beam switching based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal, and if so, perform inter-satellite beam switching based on the low-orbit satellite ephemeris, and if not, continue to track the satellite based on the initial ephemeris;

[0014] The random access memory is used to store the low-orbit satellite ephemeris.

[0015] Based on the above technical solution, this specification can achieve the following technical effects:

[0016] The method can realize stable switching of antenna beams between different low-orbit satellites, ensure that the antenna beam of the satellite communication terminal is always pointing to the overhead satellite, and solve the difficult problems of congestion in reading and storing ephemeris information of multiple stars and contradiction in storage area allocation through ephemeris storage and storage update methods; solve the problems of channel fading and poor communication stability caused by inter-satellite switching by judging whether to perform inter-satellite beam switching, thereby solving the problem of unstable data link or communication interruption caused by problems in the inter-satellite beam switching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flowchart of a method for implementing inter-satellite beam switching of a low-orbit satellite communication terminal in one embodiment of the present invention.

[0018] Figure 2 The figure is a flow chart of a method for implementing inter-satellite beam switching in one embodiment of the present invention.

[0019] Figure 3 Schematic diagram of formatting the ephemeris storage area in one embodiment of the present invention.

[0020] Figure 4 The figure is a schematic diagram of inter-satellite beam switching performed by a satellite communication terminal in one embodiment of the present invention.

[0021] Figure 5 The figure is a schematic diagram of the structure of a satellite communication terminal medium in one embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0023] It should be noted that, in order to clearly explain the content of the present invention, the present invention specifically cites multiple embodiments to further illustrate different implementations of the present invention, wherein the multiple embodiments are enumerated rather than exhaustive. In addition, for the sake of brevity of explanation, the contents mentioned in the previous embodiments are often omitted in the subsequent embodiments. Therefore, the contents not mentioned in the subsequent embodiments can refer to the previous embodiments accordingly.

[0024] Example 1

[0025] Please refer to Figure 1 , Figure 1 The figure shows a method for implementing inter-satellite beam switching of a low-orbit satellite communication terminal provided by this embodiment. In this embodiment, the method includes:

[0026] Step 102, tracking the target satellite based on the acquired initial ephemeris, and receiving the satellite signal of the target satellite;

[0027] Step 104, receiving the low-orbit satellite ephemeris sent by the low-orbit satellite communication system and updating the ephemeris;

[0028] In this embodiment, before step 104, the following steps are also included:

[0029] Step 1031, dividing the ephemeris storage space from the fast storage area inside the satellite communication terminal;

[0030] Step 1032, formatting the ephemeris storage space in matrix format to obtain an ephemeris storage area.

[0031] In this embodiment, the capacity of the ephemeris storage space must be sufficient to store at least 24 hours of ephemeris data.

[0032] In this embodiment, one implementation of step 104 is:

[0033] Step 202, based on the low-orbit satellite ephemeris sent by the low-orbit satellite communication system, obtain a plurality of ephemeris data of each low-orbit satellite;

[0034] Step 204, based on the first ephemeris information of each ephemeris data, obtain the time of each ephemeris data;

[0035] Step 206: Write the ephemeris data of each low-orbit satellite into the corresponding position of the ephemeris storage area in chronological order.

[0036] In this embodiment, if all corresponding positions in the ephemeris storage area are used, the oldest ephemeris data are erased in sequence, and the latest ephemeris data are written in.

[0037] Step 106, based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal, determine whether to perform inter-satellite beam switching. If yes, perform inter-satellite beam switching based on the low-orbit satellite ephemeris. If no, continue to track the satellite based on the initial ephemeris.

[0038] In this embodiment, judging whether to perform inter-satellite beam switching based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal includes:

[0039] Step 302, generating a first determination condition and a second determination condition based on a minimum signal-to-noise ratio threshold for inter-satellite beam switching, a total service time of the target satellite, and a minimum remaining service time for inter-satellite beam switching;

[0040] Step 304, determine whether the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal meet the first determination condition or the second determination condition. If so, determine that inter-satellite beam switching is required; if not, determine that inter-satellite beam switching is not required.

[0041] In this embodiment, the first judgment condition is that the signal-to-noise ratio of the satellite signal of the target satellite is less than the minimum signal-to-noise ratio threshold, and the remaining service time of the target satellite is greater than or equal to the minimum remaining service time and less than or equal to one half of the total service time; the second judgment condition is that the remaining service time of the target satellite is less than or equal to the minimum remaining service time.

[0042] In this embodiment, the inter-satellite beam switching based on the low-orbit satellite ephemeris includes:

[0043] Step 402, based on the low-orbit satellite ephemeris, obtaining the ephemeris start time and ephemeris end time of each low-orbit satellite;

[0044] Step 404, screening low-orbit satellites based on the current time and the ephemeris start time and ephemeris end time of each low-orbit satellite, to obtain a plurality of available satellites and a first set consisting of the satellites;

[0045] Step 406, based on the distance between each available satellite and the satellite communication terminal and a preset communication distance threshold, the available satellites are screened to obtain a plurality of relatively good satellites and a second set consisting of the satellites;

[0046] In this embodiment, one implementation of step 406 is:

[0047] It is determined in turn whether the distance between each available satellite and the satellite communication terminal is greater than a preset communication distance threshold. If so, the available satellite is removed from the first set. If not, the available satellite is determined to be a better satellite, and several better satellites and a second set consisting of them are obtained.

[0048] Step 408, based on the position information and attitude information of the satellite communication terminal, calculate the total service time and execution angle of each preferred satellite in the second set; the execution angle is the angle at which the beam of the satellite communication terminal points to the corresponding preferred satellite;

[0049] Step 410, based on the total service time, execution angle and corresponding preset weight coefficient of each superior satellite, a priority value for each superior satellite to perform inter-satellite beam switching is calculated;

[0050] Step 412, taking the preferred satellite with the largest priority value as the optimal satellite;

[0051] Step 414: Based on the ephemeris data of the optimal satellite, control the antenna beam to point to the optimal satellite, and complete the inter-satellite beam switching.

[0052] Specifically, the workflow of this method to implement beam switching is as follows: Figure 2 As shown, after the satellite communication terminal of the low-orbit satellite is turned on,

[0053] Step S01, obtaining initial ephemeris (by pre-storing or manually inputting into the satellite communication terminal); then the satellite communication terminal starts the satellite tracking function according to the initial ephemeris,

[0054] Step S02: After successfully tracking the satellite, establish a communication link with the satellite.

[0055] Step S03: Implement satellite communication function; at this time, the low-orbit satellite communication system will send low-orbit satellite ephemeris to the satellite communication terminal as needed, and the satellite communication terminal will update the ephemeris.

[0056] Step S04: Since low-orbit satellites orbit the earth at a high speed, the terminal needs to make inter-satellite beam switching decisions based on the current signal-to-noise ratio of the received satellite signal and the remaining available time,

[0057] In this embodiment, a method for storing ephemeris is designed in step S04:

[0058] First, when the satellite communication terminal (satellite communication terminal) formats a certain amount of storage space on its internal fast storage area (DDR in this case) as ephemeris storage space;

[0059] Secondly, according to the actual use situation, the capacity of the storage area needs to be sufficient to store at least 24 hours of ephemeris data. In the present invention, the ephemeris storage area is provided with a storage space that can store about 800,000 ephemeris data.

[0060] Finally, the storage area is formatted in an M×N matrix format, such as Figure 3 , where M means that the ephemeris data of M stars can be stored, and N means N ephemeris data of each star. In the present invention, M is 1024 and N is 1000.

[0061] In step S04, after obtaining the latest ephemeris information, the terminal will store the ephemeris data in the ephemeris storage area. The satellite communication terminal will determine the time of the ephemeris according to the first ephemeris information of the satellite ephemeris, and write the ephemeris of each satellite into the storage space in chronological order. When the storage space is used up, the earliest ephemeris will be erased in turn and continue to be written.

[0062] Step S05: If inter-satellite beam switching is required, the target satellite for inter-satellite beam switching is selected based on a comprehensive judgment of the available time of available satellites in the current visible range, the satellite ephemeris and other information. The terminal then reads the ephemeris of the target satellite and issues a control command to point the antenna beam to the target satellite, completing the inter-satellite beam switching.

[0063] In this embodiment, a judgment method is proposed in step S05, which is a judgment method based on time and signal-to-noise ratio.

[0064] During the communication process, the satellite communication terminal will obtain the signal-to-noise ratio of the current satellite signal and the remaining service time of the current satellite in real time. Suppose the signal-to-noise ratio of the current satellite signal received is Q, the minimum signal-to-noise ratio threshold for beam switching is Qm, the total available service time of the current satellite is TT, the remaining service time of the current satellite is Tla, and the minimum remaining service time for beam switching is Tm.

[0065] This method is specifically implemented as follows:

[0066] (1) First judgment condition: When Q < Qm and Tm ≤ Tla ≤ TT / 2, the inter-satellite handover process is immediately started;

[0067] (2) The second judgment condition: When Tla≤Tm, the inter-satellite handover process is started.

[0068] This method can ensure that the communication signal-to-noise ratio of the satellite communication terminal meets the communication requirements in real time, avoiding a significant decline in the signal-to-noise ratio, which leads to the problem of poor communication quality during beam switching.

[0069] In step S06, a satellite communication terminal beam switching strategy is proposed, which can select a better target satellite.

[0070] There are M available low-orbit satellites in space, and the low-orbit satellites in space form a low-orbit satellite communication network, such as Figure 4 As shown in the figure, there are multiple satellites available above the target. When the satellite communication terminal starts inter-satellite beam switching, the terminal's beam needs to be pointed to the target satellite. Here, a satellite selection strategy based on satellite distance and remaining satellite service time is proposed. The specific implementation method is as follows:

[0071] Assume that the start time of the ephemeris in the satellite ephemeris is Ts, the end time of the ephemeris is Td, and the current time is T. According to the phased array terminal and satellite ephemeris information, the available satellite ephemeris is screened. The screening method is to use the time judgment method, that is, the satellites within Ts≤T≤Td to form an available satellite set S1, S1 = {satellite 1 ephemeris, satellite 2 ephemeris, ..., satellite M ephemeris};

[0072] From the set S1, the distance L between the phased array terminal and the satellite M is calculated based on the ephemeris and the terminal's own position information. Because the greater the distance between the target satellite and the satellite communication terminal, the greater the communication link loss, a communication distance threshold Lq is set. If L>Lq, satellite M is removed from the set S1, and finally a new available satellite set S2 is obtained.

[0073] From the available satellite set S2, the total available service time of each satellite in the current S2 is calculated as TT through the positioning and attitude information and ephemeris information of the phased array terminal, and the execution angle θ of the satellite's terminal beam pointing to the satellite is calculated, where θ is the angle between the current beam pointing and the ground plane.

[0074] Using the weighted algorithm, only the values ​​of TT and θ are used, and different weight coefficients x and y are assigned respectively to calculate the inter-satellite beam switching priority PA, where PA = xTT + yθ. The numbers of the satellites in the satellite set S2 are sorted from large to small according to their PA values, and an ordered list K of available satellite numbers is obtained, K = [satellite m1, satellite m2, ...]. Satellites with higher PA values ​​are preferred target signal satellites, ensuring the quality of communication signals and providing good conditions for further network access and link establishment.

[0075] The satellite communication terminal reads the ephemeris data of satellite m1 according to list K, and then controls the current beam to point to the target satellite m1, completing the inter-satellite beam switching.

[0076] In summary, this method can realize the stable switching of antenna beams between different low-orbit satellites, ensure that the antenna beam of the satellite communication terminal is always pointing to the overhead satellite, and solve the problems of congestion in reading and storing ephemeris information of multiple stars and the contradiction in storage area allocation through ephemeris storage and storage update methods; by judging whether to perform inter-satellite beam switching, the problems of channel fading and poor communication stability caused by inter-satellite switching are solved, thereby solving the problem of unstable data link or communication interruption caused by problems in the inter-satellite beam switching process.

[0077] Example 2

[0078] Please refer to Figure 5 , Figure 5 The figure shows a medium for performing inter-satellite beam switching of a low-orbit satellite communication terminal provided by this embodiment. In this embodiment, the medium includes:

[0079] A communication baseband, used to control the antenna to track the target satellite based on the acquired initial ephemeris, receive and process the satellite signal of the target satellite, and receive the low-orbit satellite ephemeris sent by the low-orbit satellite communication system;

[0080] Combined inertial navigation, used to obtain the position and attitude information of satellite communication terminals;

[0081] A control processing chip, used to control the antenna;

[0082] A computing and processing chip, used to determine whether to perform inter-satellite beam switching based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal, and if so, perform inter-satellite beam switching based on the low-orbit satellite ephemeris, and if not, continue to track the satellite based on the initial ephemeris;

[0083] The random access memory is used to store the low-orbit satellite ephemeris.

[0084] Specifically, Figure 4 As shown, the medium includes a communication baseband, an antenna, a combined inertial navigation, a control processing chip, a computing processing chip, a random access memory, and a memory.

[0085] The communication baseband completes the signal processing. It cooperates with the antenna to complete the satellite communication network access and communication functions of the satellite communication terminal medium and realize the acquisition of ephemeris.

[0086] The antenna transmits and receives signals, and the antenna beam pointing is controlled by the satellite communication terminal;

[0087] Combined inertial navigation can obtain the attitude and position information of the current satellite communication terminal, and assist the satellite communication terminal to complete the inter-satellite beam switching strategy;

[0088] The control chip realizes the acquisition and distribution of satellite communication terminal information and completes the control of the antenna;

[0089] The computing and processing chip implements the various strategies and algorithms in the present invention;

[0090] The clock, random access memory and memory memory assist in realizing data storage and the realization of the above strategies and algorithms. The control chip selected in the present invention is FPGA, the computing processing chip is ARM, the random access memory is DDR memory, and the memory memory is Flash memory.

[0091] Based on this, the medium can realize stable switching of antenna beams between different low-orbit satellites, ensure that the antenna beam of the satellite communication terminal is always pointing to the overhead satellite, and solve the problems of congestion in reading and storing ephemeris information of multiple stars and contradiction in storage area allocation through ephemeris storage and storage update methods; by judging whether to perform inter-satellite beam switching, the problems of channel fading and poor communication stability caused by inter-satellite switching are solved, thereby solving the problem of unstable data link or communication interruption caused by problems in the inter-satellite beam switching process.

[0092] The above is a description of a specific embodiment of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the specific order or sequential order shown in the process depicted in the drawings is not necessarily required to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0093] The above is only an embodiment of the present application and is 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 in the scope of the claims of the present application.

Claims

1. A method for implementing inter-satellite beam switching of a low-orbit satellite communication terminal, characterized in that: include: Tracking the target satellite based on the acquired initial ephemeris and receiving the satellite signal of the target satellite; Receive the low-orbit satellite ephemeris sent by the low-orbit satellite communication system and update the ephemeris; Based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal, it is determined whether to perform inter-satellite beam switching. If so, inter-satellite beam switching is performed based on the low-orbit satellite ephemeris. If not, satellite tracking continues based on the initial ephemeris.

2. The method according to claim 1, characterized in that Before receiving the low-orbit satellite ephemeris sent by the low-orbit satellite communication system and updating the ephemeris, the method further includes: Separating ephemeris storage space from a fast storage area inside a satellite communication terminal; The ephemeris storage space is formatted in matrix form to obtain an ephemeris storage area.

3. The method according to claim 2, characterized in that The capacity of the ephemeris storage space must be sufficient to store at least 24 hours of ephemeris data.

4. The method according to claim 3, characterized in that: The receiving of low-orbit satellite ephemeris sent by the low-orbit satellite communication system and updating the ephemeris comprises: Based on the low-orbit satellite ephemeris sent by the low-orbit satellite communication system, a plurality of ephemeris data of each low-orbit satellite are obtained; Based on the first ephemeris information of each ephemeris data, obtaining the time of each ephemeris data; Several pieces of ephemeris data of each low-orbit satellite are written into the corresponding positions of the ephemeris storage area in chronological order.

5. The method according to claim 4, characterized in that If all the corresponding positions in the ephemeris storage area are used, the oldest ephemeris data will be erased in turn, and the latest ephemeris data will continue to be written.

6. The method according to claim 1, characterized in that The determining whether to perform inter-satellite beam switching based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal includes: Generate a first determination condition and a second determination condition based on a minimum signal-to-noise ratio threshold for inter-satellite beam switching, a total service time of the target satellite, and a minimum remaining service time for inter-satellite beam switching; It is determined whether the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal meet the first determination condition or the second determination condition. If so, it is determined that inter-satellite beam switching is required; if not, it is determined that inter-satellite beam switching is not required.

7. The method according to claim 6, characterized in that The first judgment condition is that the signal-to-noise ratio of the satellite signal of the target satellite is less than the minimum signal-to-noise ratio threshold, and the remaining service time of the target satellite is greater than or equal to the minimum remaining service time and less than or equal to one half of the total service time; the second judgment condition is that the remaining service time of the target satellite is less than or equal to the minimum remaining service time.

8. The method according to claim 1, characterized in that: The inter-satellite beam switching based on the low-orbit satellite ephemeris includes: Based on the low-orbit satellite ephemeris, the ephemeris start time and ephemeris end time of each low-orbit satellite are obtained; Screening low-orbit satellites based on the current time and the ephemeris start time and ephemeris end time of each low-orbit satellite to obtain a number of available satellites and a first set consisting of the satellites; Based on the distance between each available satellite and the satellite communication terminal and a preset communication distance threshold, the available satellites are screened to obtain a plurality of better satellites and a second set consisting of the better satellites; Based on the position information and attitude information of the satellite communication terminal, the total service time and the execution angle of each preferred satellite in the second set are calculated; the execution angle is the angle at which the beam of the satellite communication terminal points to the corresponding preferred satellite; Based on the total service time, execution angle and corresponding preset weight coefficient of each superior satellite, the priority value of each superior satellite for inter-satellite beam switching is calculated; The better satellite with the largest priority value is taken as the optimal satellite; Based on the ephemeris data of the optimal satellite, the antenna beam is controlled to point to the optimal satellite to complete inter-satellite beam switching.

9. The method according to claim 8, characterized in that The method of screening the available satellites based on the distance between each available satellite and the satellite communication terminal and the preset communication distance threshold to obtain a plurality of relatively optimal satellites and a second set consisting of the same includes: determining in turn whether the distance between each available satellite and the satellite communication terminal is greater than the preset communication distance threshold; if so, removing the available satellite from the first set; if not, determining that the available satellite is a relatively optimal satellite, and obtaining a plurality of relatively optimal satellites and a second set consisting of the same.

10. A medium for performing inter-satellite beam switching in a low-orbit satellite communication terminal, characterized in that: include: Communication baseband, antenna, combined inertial navigation, control processing chip, computing processing chip, random access memory; A communication baseband, used to control the antenna to track the target satellite based on the acquired initial ephemeris, receive and process the satellite signal of the target satellite, and receive the low-orbit satellite ephemeris sent by the low-orbit satellite communication system; Combined inertial navigation, used to obtain the position and attitude information of satellite communication terminals; A control processing chip, used to control the antenna; A computing and processing chip, used to determine whether to perform inter-satellite beam switching based on the remaining service time of the target satellite and the signal-to-noise ratio of the satellite signal, and if so, perform inter-satellite beam switching based on the low-orbit satellite ephemeris, and if not, continue to track the satellite based on the initial ephemeris; The random access memory is used to store the low-orbit satellite ephemeris.

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