Comprehensive prediction method for uplink transmission advance of low earth orbit satellite communication, storage medium and electronic equipment

Abstract

The invention provides a low-orbit satellite communication uplink transmission advance comprehensive prediction method, a storage medium and electronic equipment, and relates to the technical field of low-orbit satellite communication, and the method comprises the steps: preparing initial parameters; performing satellite ephemeris calculation according to the initial parameters and correcting local time; the local time and the satellite transit starting time are continuously compared, and the position coordinates of the ground user terminal are calculated at each stepping time after the satellite transit starting time; synchronously reading ephemeris data, and carrying out star-end transmission delay calculation; determining an uplink sending lead according to the satellite-end transmission time delay, and performing uplink synchronization; and after uplink synchronization, the ground user terminal sends a ranging frame to the satellite when the service is idle, and the satellite processing load demodulates the ranging frame to obtain an uplink time delay error and feeds the uplink time delay error back to the ground user terminal. According to the method, the accurate and rapid prediction of the uplink sending advance in low-orbit satellite communication is realized, and rapid synchronization of an uplink is facilitated.

Description

Technical Field

[0001] The present application relates to the technical field of low-orbit satellite communications, and in particular to a method, storage medium and electronic device for comprehensively estimating the advance amount of uplink transmission in low-orbit satellite communications. Background Art

[0002] In recent years, with the rise of the satellite Internet boom, low-orbit satellite communications have regained widespread attention with their low latency, large capacity, global coverage and cost advantages. A notable feature of low-orbit satellite communications is that there is a dynamic transmission delay between the ground user terminals (hereinafter referred to as terminals) and the satellites in the system due to the relatively high-speed movement, resulting in the uplink signals sent by each terminal not being able to reach the satellite strictly according to the established timing. This brings severe uplink synchronization challenges to the low-orbit satellite communication system that adopts a burst system. In addition, due to the considerations of versatility and reducing processing resource consumption, the satellite generally does not deal with the impact of the dynamic delay between the satellite and the ground. Therefore, this problem can only be solved by each terminal.

[0003] The key to solving this problem is that each terminal must accurately predict the dynamic transmission delay between the satellite and the terminal, so as to determine the advance amount of uplink transmission. Considering that the downlink is less affected by dynamic delay and synchronization is easier, one idea is to broadcast the satellite position information in the downlink channel. After the terminal receives the satellite position information, it can calculate the satellite-to-terminal transmission delay in combination with its own position information. The problem is that the satellite position data received by the terminal has lagged behind the actual position of the satellite, so this method is not suitable for occasions with high delay error requirements. Another type is a closed-loop delay prediction method based on the "preset-detection-feedback-correction" process. After the initial synchronization, this method requires real-time interaction of delay correction information on a dedicated synchronization channel and signaling channel. The resource consumption and implementation complexity are high and time-consuming. For low-orbit satellite communication systems with frequent satellite switching, the communication time under a satellite is generally only a few minutes. The uplink delay prediction time is too long, which will reduce the communication QOS and user experience. Therefore, this method also has certain limitations when applied to low-orbit satellite communication systems. Summary of the invention

[0004] The embodiments of the present application provide a comprehensive prediction method, storage medium and electronic device for uplink transmission advance of low-orbit satellite communication. Through this method, the terminal does not need to receive the ephemeris data broadcast by the satellite from the downlink channel in advance, but solves the satellite ephemeris locally according to the six satellite orbit numbers and directly performs open-loop satellite-to-terminal transmission delay prediction in combination with the high-precision position data provided by the satellite navigation receiver. In view of the problem that the satellite ephemeris solution error increases over time, this method designs a timely uplink delay error detection and feedback scheme. The terminal can use this scheme to obtain the current uplink delay error when the service is idle and update the six satellite orbit numbers in a timely manner accordingly, avoiding the impact of the cumulative diffusion of the ephemeris solution error on the satellite-to-terminal delay prediction.

[0005] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by the practice of the present application.

[0006] According to a first aspect of an embodiment of the present application, a method for comprehensively estimating an uplink transmission advance amount for low-orbit satellite communication is provided, comprising:

[0007] Prepare initial parameters;

[0008] Perform satellite ephemeris calculation according to the initial parameters to obtain ephemeris data;

[0009] Correcting the local time of the ground user terminal according to the initial parameters;

[0010] Continuously compare the corrected local time with the start time of satellite transit, and calculate the position coordinates of the ground user terminal at each step time after the start time of satellite transit;

[0011] Synchronously read ephemeris data and calculate satellite-to-terminal transmission delay;

[0012] Determine the uplink transmission advance amount according to the satellite-to-terminal transmission delay and perform uplink synchronization;

[0013] After uplink synchronization, the ground user terminal sends ranging frames to the satellite when the service is idle. The on-board processing payload demodulates the ranging frames to obtain the uplink delay error.

[0014] In some embodiments of the present application, based on the above scheme, the preparing initial parameters includes:

[0015] Obtain the six orbital numbers of the standby satellite from the satellite operation and control center or on-board broadcast;

[0016] Obtaining the position and velocity data of the user station from the satellite navigation receiver;

[0017] Obtain high-precision time information and pulse-per-second from satellite navigation receivers;

[0018] The time step t for sending the star-to-end transmission delay data is determined according to the uplink transmission delay adjustment period, the star-to-end transmission delay calculation time and the time for sending the star-to-end transmission delay data through the internal bus. step .

[0019] In some embodiments of the present application, based on the above-mentioned solution, performing satellite ephemeris calculation according to the initial parameters to obtain ephemeris data includes:

[0020] The satellite ephemeris is calculated based on the six orbital numbers of the standby satellite to obtain the satellite transit start time t start As the starting point, t stepThe time-stepped ephemeris data sets are merged and stored.

[0021] In some embodiments of the present application, based on the above-mentioned solution, the correcting the local time of the ground user terminal according to the initial parameters includes:

[0022] The local time of the ground user terminal is corrected according to the high-precision time information and the second pulse.

[0023] In some embodiments of the present application, based on the above scheme, the step of calculating the position coordinates of the ground user terminal at each step time after the start time of the satellite transit includes:

[0024] Use formula (1) to determine the step time t i ;

[0025] t i =t start +t step , i = 0, 1, 2…; (1)

[0026] Among them, t start is the starting time of satellite transit, t step The time step for sending satellite-to-terminal transmission delay data;

[0027] Based on the step time t i , use formula (2) to calculate the ground user terminal at step time t i The position coordinates (x u (t i ),y u (t i ),z u (t i ));

[0028]

[0029] Among them, (vx u (t′),vy u (t′),vz u (t′)) are the velocity coordinates of the ground user terminal given by the satellite navigation receiver most recently.

[0030] In some embodiments of the present application, based on the above-mentioned solution, the synchronous reading of ephemeris data and calculation of satellite-to-terminal transmission delay include:

[0031] Read t in the ephemeris data storage area i The ephemeris data at the time and combined with t i The position coordinates of the ground user terminal at the moment, use formula (3) to calculate the star-to-terminal transmission delay, and get the star-to-terminal transmission delay;

[0032]

[0033] Among them, τ s (t i ) indicates t i Time satellite-to-terminal transmission delay, (x u (t i ),y u (t i ),z u (t i )) indicates that the ground user terminal is at t i The position coordinates at the moment, (x s (t i ),y s (t i ),z s (t i )) means t i Ephemeris data at the time.

[0034] In some embodiments of the present application, based on the above solution, determining the uplink transmission advance amount according to the satellite-to-terminal transmission delay includes:

[0035] Based on the satellite-to-terminal transmission delay τ s , Downlink receiving synchronization processing delay τ p and the transmission time t of the next transmission subframe of the ground user terminal ut Determine the uplink transmission advance τ ad ;

[0036] τ ad =t ut -2τ s -τ p (4)

[0037] In some embodiments of the present application, based on the above solution, it also includes:

[0038] The on-board processing payload sends the uplink delay error to the ground user terminal via the downlink signaling channel;

[0039] The ground user terminal determines the relationship between the current uplink delay error and the delay error threshold, gives an alarm message and determines whether the six orbital numbers need to be updated. If the orbital numbers need to be updated, the latest six satellite orbital numbers are collected from the downlink broadcast channel. The latest six satellite orbital numbers are used for satellite ephemeris calculation during the next communication.

[0040] According to a second aspect of an embodiment of the present application, a computer-readable storage medium is provided, wherein the storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer executes the method according to the first aspect.

[0041] According to a third aspect of an embodiment of the present application, there is provided an electronic device, including: a memory and a processor;

[0042] The memory is used to store computer instructions;

[0043] The processor is used to call the computer instructions stored in the memory so that the electronic device executes the method as described in the first aspect.

[0044] The technical solution of this application has the following beneficial effects:

[0045] The uplink open-loop transmission delay estimation is realized by performing ephemeris solution at the local terminal based on the six satellite orbit numbers. It has significant advantages such as being fast, simple, and occupies few resources. It effectively solves the problem of difficult prediction of uplink transmission advance in low-orbit satellite communications, and can assist in achieving fast uplink synchronization.

[0046] Aiming at the problem that the satellite ephemeris solution error increases over time, a timely closed-loop delay estimation scheme is proposed. This scheme occupies less resources, has little impact on business communications, and makes up for the shortcomings of open-loop delay error estimation.

[0047] This method combines open-loop and closed-loop satellite-to-terminal delay prediction methods, effectively solving the problem of difficult uplink fast synchronization in low-orbit burst satellite communication systems, and has good applicability to ground fixed terminals or "mobile communication" terminals.

[0048] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0050] Figure 1 A schematic flow chart of a method for comprehensively estimating an uplink transmission advance amount for low-orbit satellite communication according to an embodiment of the present application is shown;

[0051] Figure 2 A schematic diagram showing a ground user terminal determining an uplink transmission advance amount according to a satellite-to-terminal transmission delay according to an embodiment of the present application is shown;

[0052] Figure 3 A schematic diagram of the composition of an on-board processing payload according to an embodiment of the present application is shown;

[0053] Figure 4 A schematic diagram showing the composition of a ground user terminal according to an embodiment of the present application is shown;

[0054] Figure 5 A schematic diagram showing an uplink ranging frame and a service frame according to an embodiment of the present application

[0055] Figure 6 A block diagram of an electronic device according to an embodiment of the present application is shown;

[0056] Figure 7 A schematic diagram of the structure of a computer system suitable for implementing an electronic device of an embodiment of the present application is shown. DETAILED DESCRIPTION

[0057] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more comprehensive and complete and fully convey the concept of the example embodiments to those skilled in the art.

[0058] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0059] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0060] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0061] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0062] Some embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0063] See also Figure 1 , shows a flow chart of a method for comprehensive estimation of uplink transmission advance amount for low-orbit satellite communication according to an embodiment of the present application.

[0064] like Figure 1 As shown, a comprehensive estimation method for uplink transmission advance of low-orbit satellite communication is presented, which specifically includes steps S100 to S700.

[0065] refer to Figure 1 , step S100, prepare initial parameters.

[0066] In some feasible embodiments, based on the above solution, the preparing initial parameters includes:

[0067] Obtain the six orbital numbers of the standby satellite from the satellite operation and control center or on-board broadcast;

[0068] Obtaining the position and velocity data of the user station from the satellite navigation receiver;

[0069] Obtain high-precision time information and pulse-per-second from satellite navigation receivers;

[0070] The time step for sending the star-to-end transmission delay data is determined according to the uplink transmission delay adjustment period, the star-to-end transmission delay calculation time and the time for sending the star-to-end transmission delay data through the internal bus.

[0071] It should be noted that for the acquisition of the six orbital numbers of the standby satellite, the parameters are initially provided by the satellite operation and control center and can be received through on-board broadcast after downlink synchronization.

[0072] It should be noted that the coordinate system of the user station position and velocity is the WGS84 coordinate system.

[0073] It should be noted that the time step t of the satellite-to-terminal transmission delay data transmission is step The determination process is as follows:

[0074]

[0075] T uadj Indicates the uplink transmission delay adjustment period, t calc is the satellite-to-terminal transmission delay calculation time, t td The star-to-terminal transmission delay is the time it takes for data to be sent through the internal bus.

[0076] Continue to refer Figure 1 , step S200, performing satellite ephemeris calculation according to the initial parameters to obtain ephemeris data.

[0077] In some feasible embodiments, based on the above solution, performing satellite ephemeris calculation according to the initial parameters to obtain ephemeris data includes:

[0078] Satellite ephemeris is calculated according to the six orbital numbers of the standby satellite to obtain ephemeris data.

[0079] It should be noted that the ephemeris data here refers to the position coordinate data of the satellite with time tags in the WGS84 coordinate system during the satellite transit time. The starting time of the time tag is the starting time of the satellite transit t start , step is t step .

[0080] It should be noted that in order to facilitate the subsequent use of the ephemeris data, the calculated ephemeris data will be stored.

[0081] Continue to refer Figure 1 , step S300, correcting the local time of the ground user terminal according to the initial parameters.

[0082] In some feasible embodiments, based on the above solution, the correcting the local time of the ground user terminal according to the initial parameters includes:

[0083] The local time of the ground user terminal is corrected according to the high-precision time information and the second pulse.

[0084] Continue to refer Figure 1 , step S400, continuously comparing the corrected local time with the satellite transit start time, and calculating the position coordinates of the ground user terminal at each step time after the satellite transit start time.

[0085] In some feasible embodiments, based on the above scheme, calculating the position coordinates of the ground user terminal at each step time after the start time of the satellite transit includes:

[0086] Use formula (2) to determine the step time t i ;

[0087] t i =tstart +t step , i = 0, 1, 2…; (2)

[0088] Among them, t start is the starting time of satellite transit, t step The time step for sending satellite-to-terminal transmission delay data;

[0089] Based on the step time t i , use formula (3) to calculate the ground user terminal at step time t i The position coordinates (x u (t i ),y u (t i ),z u (t i ));

[0090]

[0091] Among them, (vx u (t′),vy u (t′),vz u (t′)) are the velocity coordinates of the ground user terminal given by the satellite navigation receiver most recently.

[0092] Continue to refer Figure 1 , step S500, synchronously read the ephemeris data and calculate the satellite-to-terminal transmission delay.

[0093] In some feasible embodiments, based on the above solution, the synchronous reading of ephemeris data and calculation of satellite-to-terminal transmission delay include:

[0094] Read t in the ephemeris data storage area i The ephemeris data at the time and combined with t i The position coordinates of the ground user terminal at the moment, use formula (4) to calculate the satellite-to-terminal transmission delay, and get the satellite-to-terminal transmission delay;

[0095]

[0096] Among them, τ s (t i ) indicates t i The star-to-end transmission delay at time (x u (t i ),y u (t i ),z u (t i )) indicates that the ground user terminal is at t i The position coordinates at the moment, (x s (t i),y s (t i ),z s (t i )) indicates that the ground user terminal is at t i Ephemeris data at the time.

[0097] Continue to refer Figure 1 , step S600, determining the uplink transmission advance amount according to the satellite-to-terminal transmission delay, and performing uplink synchronization.

[0098] In some feasible embodiments, based on the above solution, determining the uplink transmission advance amount according to the satellite-to-terminal transmission delay includes:

[0099] Based on the satellite-to-terminal transmission delay τ s , Downlink receiving synchronization processing delay τ p and the transmission time τ of the next transmission subframe of the ground user terminal ut Determine the uplink transmission advance τ ad ;

[0100] τ ad =t ut -2τ s -τ p (5)

[0101] For example, Figure 2 As shown, assume that the sending subframe 0 and receiving subframe 0 of each frame on the satellite are allocated to the current terminal, the sending and receiving frames on the satellite are scheduled to start at the same time, and the sending and receiving frames of the terminal are scheduled to start at the same time and lag behind the satellite by τ s0 +τ p , τ s0 is the satellite-to-terminal transmission delay during downlink synchronization, τ p is the downlink reception synchronization processing delay, which is a known fixed value. uadj In the absence of satellite-to-terminal transmission delay, the terminal determines the transmission time of the next subframe 0 as t according to the uplink frame plan. ut , in order to ensure that the next subframe 0 of the terminal arrives at the next receiving subframe 0 on time, the uplink transmission relative to t ut The advance amount is:

[0102] τ ad =t ut -2τ s -τ p (5)

[0103] where τ s is the distance τ ad The most recent estimated transmission delay is obtained by formula (4).

[0104] Continue to refer Figure 1 , step S700, after the uplink is synchronized, the ground user terminal sends a ranging frame to the satellite when the service is idle, and the satellite processing payload demodulates the ranging frame to obtain the uplink delay error.

[0105] It should be noted that the ranging function is triggered only when there is no service data.

[0106] In some feasible embodiments, based on the above scheme, reference Figure 1 , the method further comprises:

[0107] Step S800, the on-board processing payload sends the uplink delay error to the ground user terminal via a downlink signaling channel;

[0108] In step S900, the ground user terminal determines the relationship between the current uplink delay error and the delay error threshold, gives an alarm message and determines whether the six orbital numbers need to be updated. If the six orbital numbers need to be updated, the latest six satellite orbital numbers are collected from the downlink broadcast channel. The latest six satellite orbital numbers are used for satellite ephemeris solution during the next communication.

[0109] The following is a specific implementation process of this method:

[0110] The composition of the on-board processing payload is as follows: Figure 3 As shown, it mainly includes user baseband processing unit, protocol processing unit and attitude and orbit control unit. Among them, the user baseband processing unit mainly completes the demodulation, decoding and deframing of uplink signals and the framing, coding and modulation of downlink signals. In addition to completing the protocol processing and data processing work during normal communication, the protocol processing unit also needs to send the satellite-terminal delay error data reported by the baseband processing unit and the satellite orbit elements provided by the attitude and orbit control unit to the terminal through the downlink signaling channel.

[0111] The main components of the terminal are as follows: Figure 4 As shown, it includes a human-machine interface, a satellite navigation receiver, an integrated control unit, a time calibration unit, an ephemeris solution processing unit, an ephemeris data storage unit, a satellite-to-terminal transmission delay calculation and sending unit, an uplink transmission delay adjustment unit, an uplink and downlink data processing unit, a baseband processing unit (including an uplink baseband processing unit and a downlink baseband processing unit), an intermediate frequency processing unit, etc. The functions of each component unit are as follows:

[0112] 1) The human-machine interface provides the terminal with the working parameters required to implement the method and displays the relevant working status during the implementation of the method;

[0113] 2) The satellite navigation receiver provides terminal position data, velocity data, Beidou whole second accumulated time and second pulse in the WGS84 coordinate system;

[0114] 3) The main function of the integrated control unit is to provide interfaces between other units in the terminal and the human-machine interface and satellite navigation receiver;

[0115] 4) The time correction unit continuously and accurately corrects the local time based on the time and second pulse provided by the satellite navigation receiver;

[0116] 5) The ephemeris calculation processing unit is mainly used to extrapolate the ephemeris parameters in the WGS84 coordinate system for a period of time in the future based on the six satellite orbit numbers through the numerical integration method;

[0117] 6) The ephemeris data storage unit is used to store the ephemeris data provided by the ephemeris solution processing unit, and the stored content is mainly the satellite position coordinates with time tags;

[0118] 7) The functions of the satellite-to-terminal transmission delay calculation and sending unit are mainly: to determine the position at the time of transmission based on the terminal position and velocity data provided by the satellite navigation receiver last time, and to calculate the satellite-to-terminal transmission delay at the time of transmission according to formula (4) in combination with the ephemeris data at the time of transmission, and then to send it to the uplink transmission delay adjustment unit through the high-speed internal bus;

[0119] 8) The function of the uplink transmission delay adjustment unit is to control the transmission advance amount of the uplink baseband processing unit in the next subframe according to the satellite-to-terminal transmission delay calculation value;

[0120] 9) The uplink baseband processing unit completes the framing, coding, modulation and other processing of uplink signaling and service data during normal business communication, and completes the framing, coding and modulation of ranging frames when the business is idle;

[0121] 10) The downlink baseband processing unit completes the demodulation, decoding and deframing of downlink signaling and service data;

[0122] 11) In addition to completing the uplink and downlink service data processing, the uplink and downlink data processing unit also realizes the baseband uplink ranging function start control and extracts the uplink delay error value fed back on the satellite from the downlink signaling channel data.

[0123] After the terminal and satellite navigation receiver are powered on and initialized, the satellite navigation receiver periodically sends the position, speed information and Beidou whole second accumulated value in the WGS84 coordinate system to the terminal through the UART serial port, and sends second pulses to the ground user terminal through the RS422 discrete interface.

[0124] The user configures the initial parameters such as the six orbital elements of the standby satellite, the starting time of the ephemeris data solution, the solution duration, and the solution step length through the human-machine interface. The starting time of the ephemeris data is determined according to the starting time of the standby satellite transit, the duration is determined by the standby satellite transit time, and the solution step length is selected according to formula (1). In this embodiment, the uplink transmission delay adjustment period is 10ms, the delay calculation time is 1ms, and the delay data transmission time is 1ms. After considering a certain margin, the solution step length is selected to be 2ms.

[0125] Considering the limitation of terminal computing and storage speed, the ephemeris solution and storage of the standby satellite must be completed before the time of use. In this embodiment, the ephemeris data of the standby satellite for the next 15 minutes can be solved and stored within 3 minutes, so the time of starting the ephemeris solution should be at least 3 minutes ahead of the time of use.

[0126] After receiving the initial parameters, the ephemeris solution processing unit starts to complete the ephemeris solution through a high-precision orbit extrapolation algorithm, and sends the ephemeris data to the ephemeris data storage unit for storage; during the communication process with the current satellite, the ephemeris data solution and storage of the next satellite are completed in advance.

[0127] The timing unit corrects the local time according to the Beidou whole second accumulated value and second pulse provided by the satellite navigation receiver. The corrected local time is sent to the satellite-to-terminal delay calculation and sending unit in the form of a 1ms timing interrupt.

[0128] The satellite-to-terminal transmission delay calculation and sending unit compares the local time with the start time of the ephemeris data. If they are equal, it means that the sending time has arrived. The user station position data at the current time is immediately obtained according to formula (3) based on the terminal position and speed data sent by the satellite navigation receiver last time. At the same time, the ephemeris data at the current time is read from the memory and the satellite-to-terminal transmission delay at the current time is calculated according to formula (4). After the calculation is completed, it is sent to the uplink transmission delay adjustment unit through the internal bus, and then an ephemeris data time step is added, and the above calculation and sending process is repeated.

[0129] The uplink transmission delay adjustment unit adjusts the transmission advance of the next uplink subframe of the terminal according to the received satellite-terminal transmission delay data according to formula (5), so that the arrival time of the transmitted subframe on the satellite is accurately aligned with the start time of receiving the subframe on the satellite, thereby assisting the uplink to complete synchronization.

[0130] The terminal automatically sends ranging frames to the onboard processing payload during service idle periods. Figure 5As shown, the uplink ranging frame and the service frame have the same frame length and symbol rate (frame length is 10ms, symbol rate is 2.56Msps), the modulation mode is BPSK, and the frame content is M sequence. The baseband processing unit demodulates, matches and filters, extracts, and stores 512 symbol data for the uplink ranging frame, and then reads 256 sample values ​​in 4x serial mode and correlates them with the local PN code to obtain 1024 correlation values ​​C(k), where k = 0 to 1023. Under the condition of decision synchronization, the uplink delay synchronization error is:

[0131]

[0132] Among them, K max In order to make C(k) reach the maximum value, a negative number τ represents leading and a positive number represents lagging.

[0133] The baseband processing unit of the onboard payload reports the estimated uplink delay error to the protocol processing unit. The protocol processing unit packages the information in the downlink signaling data and sends it to the terminal through the downlink signaling channel. After receiving the uplink delay error estimation data, the terminal compares it with the uplink delay error threshold (set to 3us in this embodiment). If the delay error reaches the threshold, the terminal actively receives the latest six satellite orbit numbers through the downlink broadcast channel, and automatically uses the latest satellite orbit numbers to calculate the satellite-to-terminal transmission delay in the next communication, and displays the alarm information on the human-machine interface until the delay error estimation value is less than the error threshold.

[0134] like Figure 6 As shown, an embodiment of the present application also provides an electronic device 600, including a memory 610, a processor 620, and a computer program 611 stored in the memory 610 and executable on the processor. When the processor 620 executes the computer program 611, the steps of the above-mentioned method for comprehensive prediction of uplink transmission advance amount of low-orbit satellite communication are implemented.

[0135] Since the electronic device introduced in this embodiment is a device used to implement a comprehensive estimation method for uplink transmission advance of low-orbit satellite communication in the embodiment of the present application, based on the method introduced in the embodiment of the present application, technical personnel in this field can understand the specific implementation mode of the electronic device of this embodiment and its various variations. Therefore, how the electronic device implements the method in the embodiment of the present application will not be introduced in detail here. As long as the equipment used by technical personnel in this field to implement the method in the embodiment of the present application is within the scope of protection of this application.

[0136] During the specific implementation process, when the computer program 611 is executed by a processor, any implementation method in the embodiments corresponding to the first aspect can be implemented.

[0137] Figure 7A schematic diagram of the structure of a computer system suitable for implementing an electronic device of an embodiment of the present application is shown.

[0138] It should be noted that Figure 7 The computer system 700 of the electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0139] like Figure 7 As shown, the computer system 700 includes a central processing unit (CPU) 701, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 702 or the program loaded from the storage part 708 to the random access memory (RAM) 703, such as executing the method described in the above embodiment. In the RAM 703, various programs and data required for system operation are also stored. The CPU 701, ROM 702 and RAM 703 are connected to each other through a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0140] The following components are connected to the I / O interface 705: an input section 706 including a keyboard, a mouse, etc.; an output section 707 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 710 as needed so that a computer program read therefrom is installed into the storage section 708 as needed.

[0141] In particular, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication section 709, and / or installed from a removable medium 711. When the computer program is executed by a central processing unit (CPU) 701, various functions defined in the system of the present application are executed.

[0142] It should be noted that the computer-readable medium shown in the embodiment of the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, - but not limited to - an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by an instruction execution system, device or device or used in combination with it. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, wherein a computer-readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0143] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0144] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. The names of these units do not, in some cases, constitute limitations on the units themselves.

[0145] As another aspect, the present application further provides a computer program product or a computer program, the computer program product or the computer program including computer instructions, the computer instructions being stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes a method for comprehensively estimating the advance amount of uplink transmission of low-orbit satellite communication described in the above embodiment.

[0146] As another aspect, the present application also provides a computer-readable medium, which may be included in the electronic device described in the above embodiment; or may exist independently without being assembled into the electronic device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by an electronic device, the electronic device implements a comprehensive prediction method for uplink transmission advance of low-orbit satellite communication described in the above embodiment.

[0147] It should be noted that, although several modules or units of the equipment for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into being embodied by multiple modules or units.

[0148] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the implementation methods of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the implementation methods of the present application.

[0149] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the embodiments disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary techniques in the art that are not disclosed in the present application. It should be understood that the present application is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for comprehensively estimating the advance amount of uplink transmission in low-orbit satellite communication, characterized in that: include: Prepare initial parameters; Perform satellite ephemeris calculation according to the initial parameters to obtain ephemeris data; Correcting the local time of the ground user terminal according to the initial parameters; Continuously compare the corrected local time with the start time of satellite transit, and calculate the position coordinates of the ground user terminal at each step time after the start time of satellite transit; Synchronously read ephemeris data and calculate satellite-to-terminal transmission delay; Determine the uplink transmission advance amount according to the satellite-to-terminal transmission delay and perform uplink synchronization; After uplink synchronization, the ground user terminal sends ranging frames to the satellite when the service is idle. The on-board processing payload demodulates the ranging frames to obtain the uplink delay error.

2. The method according to claim 1, characterized in that The preparing of initial parameters comprises: Obtain the six orbital numbers of the standby satellite from the satellite operation and control center or on-board broadcast; Obtaining the position and velocity data of the user station from the satellite navigation receiver; Obtain high-precision time information and pulse-per-second from satellite navigation receivers; The time step t for sending the star-to-end transmission delay data is determined according to the uplink transmission delay adjustment period, the star-to-end transmission delay calculation time and the time for sending the star-to-end transmission delay data through the internal bus. step .

3. The method according to claim 2, characterized in that The performing satellite ephemeris calculation according to the initial parameters to obtain ephemeris data includes: The satellite ephemeris is calculated based on the six orbital numbers of the standby satellite to obtain the satellite transit start time t start As the starting point, t step The time-stepped ephemeris data sets are merged and stored.

4. The method according to claim 2, characterized in that: The correcting the local time of the ground user terminal according to the initial parameters includes: The local time of the ground user terminal is corrected according to the high-precision time information and the second pulse.

5. The method according to claim 3, characterized in that: The step of calculating the position coordinates of the ground user terminal at each step time after the start time of the satellite transit comprises: Use formula (1) to determine the step time t i ; t i =t start +t step ,i=0,1,2…; (1) Among them, t start is the starting time of satellite transit, t step The time step for sending satellite-to-terminal transmission delay data; Based on the step time t i , use formula (2) to calculate the ground user terminal at step time t i The position coordinates (x u (t i ),y u (t i ),z u (t u )); Among them, (vx u (t′),vy u (t′),vz u (t′)) are the velocity coordinates of the ground user terminal given by the satellite navigation receiver most recently.

6. The method according to claim 5, characterized in that The synchronous reading of ephemeris data and calculation of satellite-to-terminal transmission delay include: Read t in the ephemeris data storage area i The ephemeris data at the time and combined with t i The position coordinates of the ground user terminal at the moment, use formula (3) to calculate the star-to-terminal transmission delay, and get the star-to-terminal transmission delay; Among them, τ s (t i ) indicates t i The star-to-end transmission delay at time (x u (t i ),y u (t i ),z u (t i )) represents the ground user terminal t i The position coordinates at the moment, (x s (t i ),y s (t i ),z s (t i )) means t i Ephemeris data at the time.

7. The method according to claim 6, characterized in that The determining the uplink transmission advance amount according to the satellite-to-terminal transmission delay includes: Based on the satellite-to-terminal transmission delay τ s , Downlink receiving synchronization processing delay τ p and the transmission time t of the next transmission subframe of the ground user terminal ut Determine the uplink transmission advance τ ad ; t ad =t ut -2t s -t p 。 (4) 8. The method according to any one of claims 2 to 7, characterized in that: Also includes: The on-board processing payload sends the uplink delay error to the ground user terminal via the downlink signaling channel; The ground user terminal determines the relationship between the current uplink delay error and the delay error threshold, gives an alarm message and determines whether the six orbital numbers need to be updated. If the orbital numbers need to be updated, the latest six satellite orbital numbers are collected from the downlink broadcast channel. The latest six satellite orbital numbers are used for satellite ephemeris solution during the next communication.

9. A computer-readable storage medium, characterized in that: The storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer executes the method according to any one of claims 1 to 8.

10. An electronic device, characterized in that: include: Memory and processor; The memory is used to store computer instructions; The processor is used to call the computer instructions stored in the memory so that the electronic device executes the method as described in any one of claims 1-8.

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