CN-122027007-A - Information order-based low-orbit satellite communication method

CN122027007ACN 122027007 ACN122027007 ACN 122027007ACN-122027007-A

Abstract

The invention discloses a low orbit satellite communication method based on information order, which comprises the following steps: S1, a low orbit satellite dynamically pre-judges effective on-demand service windows according to the orbit ephemeris and a preset communication duration threshold value, and pre-configures communication link parameters of each window, and the method has the advantages that: the defects (short overhead time and intermittent link) of the low-orbit satellite are converted into controllable resources through a dynamic window activation, on-board intelligent scheduling and satellite-ground cooperative transmission trinity mechanism; the method not only intelligently selects a valuable time window for service so as to save energy, but also utilizes multiple transit opportunities to finish reliable transmission of large files like relay games, solves the problems that the traditional satellite broadcasting mode is unidirectional and fixed in content, and the traditional satellite communication mode is high in resource occupation and difficult to support massive non-real-time large data transmission pain points, and enables satellites to provide personalized and on-demand data services for massive users concurrently like ground internet services.

Inventors

SHI ZHONGBO
SHEN HAN
TANG CHAOJUN
LU JIANFENG

Assignees

南京典格通信科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The low-orbit satellite communication method based on information order is characterized by comprising the following steps: s1, dynamically pre-judging effective on-demand service windows by a low-orbit satellite according to the orbit ephemeris and a preset communication duration threshold value, and pre-configuring communication link parameters of each window; s2, after the low orbit satellite enters an effective order service window, establishing a satellite-ground link with a coverage user terminal, and broadcasting an encrypted order file list and a one-time dynamic random number which is only effective in the window; S3, the user terminal receives and analyzes the file list, generates a request for requesting after selecting a target file, and sends back the request to the low orbit satellite through an uplink in the effective window; S4, the user terminal uses the private key, and combines the received one-time dynamic random number and the current time stamp to generate and send an SM2 digital signature; S5, the low orbit satellite gathers all legal on-demand requests to form a queue, and decides a specific service mode of each request according to on-board caching, adjacent satellite resources, satellite-ground link quality and request characteristics; S6, for a request for deciding to be directly served by the satellite, the low-orbit satellite starts a digital beam forming system, generates multi-point beams to point to each target user terminal, and utilizes space division multiplexing to concurrently transmit data of different files; s7, continuously issuing a data stream by the low-orbit satellite, recording a transmission breakpoint if the transmission is not completed, and recovering the transmission from the breakpoint when the link is established with the same user terminal next time; s8, the ground data processing center gathers the data fragments of the same file which are received by the user terminal or the ground station and are downloaded for many times from the same satellite or different satellites, and sequences, de-duplicates and reorganizes the data fragments according to the file identification to restore the complete original file; s9, the ground data processing center distributes the recombined complete file to a requesting user through a ground network, and the user feeds back a confirmation message to the satellite after checking the complete file; s10, uploading updated processing modules and software when the low-orbit satellite flies through the ground gateway station, and calling corresponding modules to process the original data on the satellite when in orbit operation, so as to generate value-added information products and add the value-added information products as new files into the on-demand list.
2. The low-orbit satellite communication method according to claim 1, wherein said step S1 comprises the steps of: A11, dynamically calculating and predicting the geometric visible relation between the low-orbit satellite and the user terminal in the preset ground service area in the future orbit period according to the data of the orbit ephemeris to obtain a theoretical visible time window; A12, setting a communication duration threshold as a service activation threshold, and comparing the duration of each theoretical visible time window predicted in the step A11 with the communication duration threshold one by one; a13, judging that the theoretical visible time window with the predicted time length being greater than the communication time length threshold is an effective on-demand service window, and pre-configuring the communication link key parameters for executing the following steps S2 to S7 for the effective on-demand service window; The key parameters comprise a working frequency point, transmitting power, a modulation coding scheme and a beam pointing initial value; a14, judging that the theoretical visible time window with the predicted duration not reaching the communication duration threshold is an invalid service window, wherein the low-orbit satellite does not activate the special communication load of the on-demand service facing the ground area.
3. The low-orbit satellite communication method according to claim 2, wherein said step S2 comprises the steps of: S21, after the low-orbit satellite enters the effective on-demand service window according to the pre-judgment in the step S1, establishing a satellite-ground communication link with an online user terminal in the coverage area of the effective on-demand service window; S22, the low-orbit satellite reads the structured on-demand file list from the satellite-borne memory and generates a disposable dynamic random number which is only valid in the service window, wherein the disposable dynamic random number is used as a core basis for security verification in the subsequent step S4; s23, the low orbit satellite associates the on-demand file list with the one-time dynamic random number, and the one-time dynamic random number is encrypted and then packaged together with the on-demand file list into a downlink control signaling data packet, and the downlink control signaling data packet is transmitted to the whole service coverage area in a broadcast mode; S24, the low orbit satellite announces in the downlink broadcast signaling, and the issued encrypted dynamic random number is used as a security anchor point which is necessary to be used when all subsequent uplink control signaling in the service window is subjected to identity authentication and replay prevention verification.
4. A low-orbit satellite communication method according to claim 3, wherein said step S3 comprises the steps of: s31, the user terminal in the service area successfully receives the order file list signaling which is from the low orbit satellite and contains the encrypted dynamic random number; s32, the application layer of the user terminal presents the on-demand file list to a user or an upper layer application, and after the user or the upper layer application selects a target file according to requirements, the user terminal automatically generates a structured on-demand request data packet containing a unique identifier of the selected target file; and S33, after the user terminal generates the structured request data packet, the request data packet is sent back to the low-orbit satellite through the established satellite uplink in the current effective request service window, and the request data packet is used as the basis for generating the security authentication request in the subsequent step S4.
5. The low-orbit satellite communication method according to claim 4, wherein said step S4 comprises the steps of: S41, the disposable dynamic random number is used as a security verification anchor point which is bound with all uplink control signaling in a service window; S42, after the user terminal generates the structured request data packet, using a private key of the user terminal to decrypt and restore the request data packet, the combination of the one-time dynamic random number and the current timestamp from the signaling in the step S2, executing digital signature by adopting an SM2 algorithm to generate a digital signature, and packaging a plaintext request and the digital signature together into an authentication request packet; the original message for the SM2 digital signature is spliced by the following formula: , In the formula, The original message is signed for SM2 and, For the on-demand request of data, Is a one-time dynamic random number, In order to be a time stamp, Representing the sequential splicing of data; S43, after receiving the authentication request packet, the low orbit satellite firstly performs signature verification, invokes a legal public key of a corresponding user terminal from a security certificate library, and performs checking calculation on an SM2 digital signature in the packet by using the legal public key; s44, after signature verification is passed, the low-orbit satellite extracts the one-time dynamic random number in the authentication request packet and compares the one-time dynamic random number with a random number generated and broadcasted by the low-orbit satellite in the service window; s45, checking whether the deviation between the time stamp in the authentication request packet and the current satellite time is within an allowable range, judging that all the on-demand requests passing verification are valid instructions, and incorporating the valid instructions into a processing queue of the subsequent step S5.
6. The low-orbit satellite communication method according to claim 5, wherein said step S5 comprises the steps of: S51, the low orbit satellite centrally sorts all legal on-demand requests passing through the verification process in the step S4 in the current service window to form an on-demand request queue to be processed; S52, aiming at the to-be-processed on-demand request queue, the low-orbit satellite analyzes the following information in real time, and provides decision basis for transmission scheduling in the following steps S6 and S7: the on-board file cache state and the storage allowance of the low-orbit satellite body; The resource state and the cache content of adjacent satellites can be detected and scheduled through inter-satellite links; the satellite-ground link quality parameters of the low-orbit satellite and each request terminal are changed in real time; the characteristic of the request queue to be processed is reflected by the request queue to be processed; And S53, generating a scheduling decision instruction for each request in the request queue to be processed according to the analysis result, wherein the scheduling decision instruction designates that the satellite provides service through a subsequent step S6, a certain specific adjacent satellite cooperatively provides service through an inter-satellite link or temporarily does not provide instant service, and the scheduling decision instruction triggers the transmission back of the acquired designated file data to a ground gateway station.
7. The low-orbit satellite communication method according to claim 6, wherein said step S7 comprises the steps of: S71, in the transmission process of the step S6, the low-orbit satellite records the successfully transmitted data quantity or the untransmitted starting position in a satellite-borne memory for each data stream which is not transmitted, so as to form the transmission breakpoint; s72, before the effective on-demand service window is closed, the low-orbit satellite continuously transmits data until the window is finished or actively interrupts transmission and stores the current transmission state; And S73, when the satellite-to-ground link is established again between the low-orbit satellite and the target user terminal next time, the corresponding transmission breakpoint information is automatically read, and the residual data is continuously transmitted from the point.
8. The low-orbit satellite communication method according to claim 7, wherein said step S8 comprises the steps of: S81, the user terminal or the ground station captures file data fragments from the low-orbit satellite downlink, wherein the file data fragments are derived from the complete original file requested by the user in the step S3 and transmitted in the steps S6 and S7; s82, all received scattered file data fragments belonging to each on-demand file are packaged into IP data packets and are collected to the ground data processing center through a ground IP network; s83, the ground data processing center extracts unified file identifiers, fragment serial numbers and source satellite identification metadata from the imported file data fragments according to protocol header information; S84, based on the extracted metadata, the ground data processing center sorts all file data fragments belonging to the same complete original file according to the fragment sequence numbers, eliminates repeated fragments, and sequentially splices the repeated fragments to restore a complete file copy consistent with the original request of the user; the reorganization process of the complete file can be quantitatively represented by the following formula: , In the formula, In order to be a complete original file after reorganization, All the data segments of the same file are aggregated, For the sequence number of the i-th fragment, Representing operations in ascending order of sequence numbers, Represents the splicing operation according to the sequencing result, Is the total number of fragments of the file.
9. The low-orbit satellite communication method according to claim 8, wherein said step S9 comprises the steps of: s91, after finishing file reorganization in the step S8, the ground data processing center immediately distributes complete original file data to the target user terminal which initiates the file on-demand request through a ground network; S92, after receiving the complete original file data, the target user terminal generates a transmission success confirmation message containing the unique identification of the file after checking, and feeds back the transmission success confirmation message to the original downlink source low orbit satellite of the file through a ground IP network and an effective satellite uplink after packaging; S93, after receiving the successful transmission confirmation message for the issued data segment, the source low orbit satellite locates and deletes the copy of the successfully received data segment from the retransmission buffer area, and releases the on-board storage resource; and S94, if the acknowledgement of the sent data segment is not received within the preset timeout period, the retransmission control mechanism automatically triggers retransmission of the data segment in a subsequent effective communication opportunity established with the related user terminal.
10. The low-orbit satellite communication method according to claim 9, wherein said step S10 comprises the steps of: S101, in a period that the low-orbit satellite flies through a ground gateway station and a high-speed feed link is established, a ground control system injects a light-weight processing model specially trained and optimized for a specific information processing task and matched software thereof into a satellite-borne memory of the low-orbit satellite; S102, scheduling satellite-borne computing resources by the low-orbit satellite according to preset conditions during in-orbit operation, calling the injected lightweight processing model to perform real-time analysis and calculation on stored original data, and executing target detection, feature extraction and data compression processing tasks; S103, after the original data are processed through the lightweight processing model, result data with high information density are generated and are value-added information products; S104, after the value-added information product is generated, the low-orbit satellite stores the value-added information product as a new independent data file into a satellite-borne memory, automatically updates an on-demand file list which is broadcasted outwards, and newly adds an entry corresponding to the value-added information product in the on-demand file list; And S105, when the user in the service area selects the value-added information product from the latest on-demand file list and initiates an on-demand request, the low-orbit satellite directly reads the stored product result file after the scheduling decision in the step S5 is carried out, and the product result file is downloaded to the user through a downlink.

Description

Information order-based low-orbit satellite communication method Technical Field The invention relates to the technical field of satellite communication, in particular to a low-orbit satellite communication method based on information ordering. Background At present, low-orbit (LEO) satellite constellations have great potential in the fields of broadband access, internet of things, earth observation, remote sensing and the like. However, its inherent link characteristics (e.g., short overhead time, intermittent connection, high dynamic mobility) also present a significant challenge to on-demand non-real-time big data services for mass users. The traditional satellite information service modes are mainly divided into two types, and the requirements are difficult to be met effectively; The first type is a broadcast push mode. The satellite broadcasts data unidirectionally and indifferently to all terminals in the coverage area within a specific frequency band and time period according to a preset program table. The mode has fixed content and lack of interactivity, and cannot respond to personalized and instant on-demand requests of users. The user can only receive passively, but can not actively select the required information. Meanwhile, since the broadcast signal is open, there is a security risk of being illegally eavesdropped, disturbed or even falsified instructions; The second type is a satellite-to-ground real-time communication mode, which is commonly found in voice, video calls and real-time data traffic. Although the mode can support bidirectional interaction, channel resources are precious, high bandwidth and power are occupied for maintaining a continuous communication session, and the mode is difficult to economically and efficiently support the concurrent transmission of large data files (such as high-resolution remote sensing images, software update packages, scientific data sets and the like) which are not real-time and are carried out by massive users. In addition, the limited on-board calculation, storage and energy resources of the satellite also restrict the bearing capacity and service flexibility of the satellite to large-flow and sudden on-demand requests; In the aspect of data transmission reliability, because the single satellite overhead time is limited, large file transmission is extremely easy to break, the prior art relies on an application layer protocol (such as an enhanced TCP variant) to carry out retransmission control in a single session, once connection is broken, the whole transmission is usually restarted from a file starting point, the efficiency is low, the user experience is poor, and a reliable seamless breakpoint continuous transmission mechanism which can utilize satellite constellation to cross a window and a satellite is lacked; In the aspect of safety access and control, an open satellite downlink broadcast channel is easy to attack, a traditional authentication mode based on a fixed key or a simple identity mark is difficult to resist against threats such as replay attack, instruction forging and the like, a continuous and high-strength safety channel is established and maintained for each terminal, huge signaling and calculation expenditure is brought, the system is not suitable for massive and intermittent connection of the Internet of things or common user terminal scenes, the current majority of low-orbit satellite systems still mainly play roles of data acquisition and downloading, the satellite downloads the whole original observed data to a ground station, and the ground large-scale data center processes and interprets the original observed data to generate a final information product, and the mode leads to long data and information conversion chain, high delay (usually several hours or even days) and occupies a large amount of precious downlink spectrum resources to transmit the original data, so that the possibility of providing real-time and dynamic information service by the satellite is limited. Disclosure of Invention The invention aims to provide a low-orbit satellite communication method based on information order, which solves the problems in the background technology. In order to achieve the above purpose, the invention provides a low orbit satellite communication method based on information ordering, which comprises the following steps: s1, dynamically pre-judging effective on-demand service windows by a low-orbit satellite according to the orbit ephemeris and a preset communication duration threshold value, and pre-configuring communication link parameters of each window; s2, after the low orbit satellite enters an effective order service window, establishing a satellite-ground link with a coverage user terminal, and broadcasting an encrypted order file list and a one-time dynamic random number which is only effective in the window; S3, the user terminal receives and analyzes the file list, generates a request for requesting after selecting a