Inter-satellite cooperative instant remote sensing system and method

Abstract

The application discloses an inter-satellite cooperative instant remote sensing system and method, and belongs to the technical field of satellite remote sensing.The application solves the problem that the existing inter-satellite relay remote sensing technology cannot meet the second-level instant remote sensing demand in the modern emergency scene when the conventional remote sensing satellite utilizes a non-dedicated relay.The method comprises the following steps: constructing an integrated composite instruction triggering mechanism to realize the parallel linkage of task issuing, link establishment and remote sensing operation; establishing a bypass straight-through flow forwarding and dynamic back pressure adaptation mechanism; setting a satellite-borne straight-through forwarding unit, which is independent of the satellite conventional data transmission storage channel, can completely bypass the satellite-borne large-capacity storage and the storage controller thereof, constructs a dedicated high-speed data straight-through link, and eliminates the storage reading and writing delay from the hardware level, thereby realizing the joint adaptation of the inter-satellite laser heterogeneous link and the satellite-ground microwave heterogeneous link.The application is suitable for the cooperative instant remote sensing between two satellites.

Description

Technical Field

[0001] This application relates to the fields of aerospace control, satellite remote sensing and inter-satellite communication collaboration, and in particular to an inter-satellite collaborative real-time remote sensing system based on joint adaptation of inter-satellite laser and satellite-ground microwave heterogeneous links. Background Technology

[0002] Real-time remote sensing technology is a core supporting technology for time-sensitive scenarios such as floods, forest fires, earthquake emergencies, and sudden environmental monitoring. Civilian emergency applications demand end-to-end real-time transmission of remote sensing data at the minute or even second level. Currently, low-orbit remote sensing satellite data acquisition mainly relies on two modes: direct transmission from ground stations and relay satellite relay from high-orbit satellites. Both have inherent technical limitations that make them unsuitable for real-time remote sensing scenarios. The direct transmission mode from ground stations is limited by the visible arc of the satellite's orbit, meaning the remote sensing satellite spends most of its time in the invisible region of the ground station. Observational data can only be temporarily stored in the satellite's large-capacity storage, resulting in data delays of several hours, which completely fails to meet the needs of emergency real-time operations. Existing relay relay schemes, represented by the US TDRSS and the domestic Tianlian relay system, rely on inter-satellite links to achieve data return from satellites in the invisible arc, solving the data acquisition problem to some extent. However, this traditional relay system has the following timeliness shortcomings:

[0003] 1. Loosely coupled task processes and multiple sequential execution steps lead to severe cumulative latency. In traditional relay systems, task command issuance, inter-satellite link scanning and establishment, remote sensing payload startup, and data storage and forwarding are all independent sequential steps. Each step involves a significant amount of invalid waiting time, and command delivery, link establishment, and remote sensing operations cannot be synchronized, resulting in a significant cumulative effect of process latency.

[0004] 2. The common practice of storing the entire scene before forwarding lacks real-time transmission capabilities. Existing relay forwarding requires waiting for the satellite to complete the imaging of the entire scene and store the data in solid-state storage before starting data forwarding. This is a typical store-then-transmit mechanism, which inherently cannot achieve second-level instantaneous return.

[0005] 3. Heterogeneous link bandwidth mismatch and lack of dedicated adaptation mechanism. Inter-satellite laser links have ultra-high transmission bandwidth of Gbps or even higher, while satellite-to-ground microwave data transmission links have relatively low bandwidth and dynamic changes. Existing technologies lack dynamic flow control, rate adaptation and real-time forwarding mechanisms for high- and low-speed heterogeneous links, which can easily lead to data congestion, packet loss and interruption due to bandwidth mismatch, making it difficult to support continuous real-time data transmission.

[0006] 4. Reliance on centralized ground control leads to delayed response. Traditional relay missions require ground-based link planning and the uploading of multiple independent commands in advance, and the satellite lacks the autonomous and rapid response capability for sudden emergency missions.

[0007] In summary, existing inter-satellite relay remote sensing solutions only achieve the basic function of transmitting satellite data back in the invisible arc segment, failing to solve the three problems of large serial delays in the process, heterogeneous link mismatch, and loose coupling between tasks and links, and thus cannot meet the second-level real-time remote sensing requirements in modern emergency scenarios. Summary of the Invention

[0008] The purpose of this invention is to address the technical problems encountered in existing inter-satellite relay systems when conducting collaborative real-time remote sensing operations using conventional remote sensing satellites without dedicated relays. These problems stem from the fact that the tasks of receiving mission commands, establishing inter-satellite laser links, and starting remote sensing payloads are executed independently and sequentially, resulting in long waiting times and hindering rapid mission response. Furthermore, the high bandwidth of inter-satellite laser links is severely mismatched with the relatively low bandwidth of satellite-to-ground microwave links, and existing technologies lack real-time adaptation mechanisms for heterogeneous links. This makes it impossible to achieve zero-wait, uninterrupted streaming real-time forwarding of remote sensing data, and to guarantee real-time remote sensing effects with end-to-end second-level latency. The invention provides an inter-satellite collaborative real-time remote sensing system and method.

[0009] The technical solution adopted by the present invention to solve the above problems is: an inter-satellite collaborative real-time remote sensing system, the system including a ground station, a relay satellite located in the visible arc segment of the ground and a target remote sensing satellite located in the invisible arc segment of the ground, the ground station generating an integrated composite command frame and sending it to the relay satellite, the composite command including a remote sensing mission information domain, an inter-satellite laser rapid link establishment auxiliary information domain and a streaming forwarding control information domain;

[0010] The relay satellite carries a dedicated joint mission command parser for receiving and parsing composite command frames;

[0011] After locking onto the inter-satellite laser link, the target satellite receives remote sensing operation instructions and begins operations;

[0012] The relay satellite has an independent onboard direct relay unit, which includes a laser frame de-framing submodule, a high-speed micro buffer, a backpressure flow control logic unit, and a microwave frame assembly submodule.

[0013] The laser frame deframe submodule is used to strip the laser protocol header, extract valid remote sensing data, and send it to a high-speed micro-buffer for instantaneous peak clipping;

[0014] The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts its transmission rate, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate.

[0015] After rate adaptation, the data undergoes real-time frame format conversion by the microwave group frame submodule to adapt to the satellite-to-ground microwave link transmission standard and continuously sends streaming data fragments to the ground station.

[0016] Furthermore, the remote sensing mission information domain includes the target area's latitude and longitude, imaging mode, and mission priority;

[0017] The link establishment auxiliary information domain includes the satellite attitude prediction angle, laser scanning window, and link preset bandwidth;

[0018] The streaming forwarding control information field includes the pass-through forwarding enable flag, micro-buffer threshold, and backpressure flow control response coefficient.

[0019] Furthermore, after receiving the integrated composite instruction frame, the joint task instruction parser synchronously triggers two parallel actions:

[0020] One action is to extract laser link establishment auxiliary parameters from the link establishment auxiliary information domain, complete the target satellite position prediction and the reduction of the scanning uncertainty area, start narrow-range rapid scanning acquisition, and establish an inter-satellite laser link;

[0021] Another action involves reconstructing the remote sensing mission instructions corresponding to the remote sensing mission information domain and the streaming forwarding configuration parameters corresponding to the streaming forwarding control information domain into an inter-satellite operation instruction frame. Specifically, this reconstruction includes:

[0022] The microwave link protocol encapsulation is stripped from the integrated composite command frame, and the payload fields of remote sensing mission commands and streaming forwarding configuration parameters are extracted. The frames are then reassembled according to the inter-satellite laser link control signaling frame format so that they can be directly embedded in the control signaling frame payload area during the laser link scanning, acquisition, and lock handshake process.

[0023] Once the laser link is locked, the target satellite can directly parse the complete operational instructions from the link control signaling without the need to establish an additional upper-level mission interaction channel.

[0024] Furthermore, the onboard direct relay unit specifically includes:

[0025] Using the laser link data frame payload as the basic unit of segmentation, each segment sequentially undergoes the following pipeline stages:

[0026] Phase 1: The laser frame de-framing submodule strips the laser protocol header from each incoming laser link data frame, extracts effective remote sensing data fragments, and sends them to the high-speed micro buffer for instantaneous peak clipping, absorbing the instantaneous rate difference between the laser link burst rate and the microwave link transmission rate.

[0027] Phase 2: The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts the transmission rate of remote sensing data of the target satellite, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate.

[0028] Phase 3: After rate adaptation, the data fragments dequeued from the micro buffer are converted from laser protocol frames to microwave protocol frames in real time by the microwave frame grouping submodule, adapting to the satellite-to-ground microwave link transmission standard, and continuously sending streaming data fragments to the ground station.

[0029] The three stages described above operate in parallel in a pipeline manner: when the Nth fragment is in the transcoding and transmission stage three, the N+1th fragment is simultaneously in the reception and peak clipping stage one, and the transmission rate of the N+2th fragment is simultaneously adjusted by the back pressure flow control closed loop of stage two. Thus, without relying on large-capacity storage, it achieves non-stacking, non-interruption, and zero-wait streaming data forwarding that simultaneously receives, adapts, transcodes, and transmits.

[0030] Secondly, the present invention provides an inter-satellite collaborative real-time remote sensing method based on the inter-satellite collaborative real-time remote sensing system as described above, the method comprising:

[0031] Step 1: The ground station integrates three types of independent information to generate an integrated composite command frame. This command frame includes a remote sensing mission information domain, an inter-satellite laser rapid link establishment auxiliary information domain, and a streaming forwarding control information domain. The command is encapsulated in a single operation and sent to the relay satellite via the satellite-to-ground microwave link.

[0032] Step 2: The relay satellite carries a joint mission command parser to receive and parse composite command frames, simultaneously triggering two parallel actions: the first path extracts laser link establishment auxiliary parameters, completes the prediction of the target satellite's position and the reduction of the scanning uncertainty area, starts narrow-range rapid scanning and acquisition, and quickly establishes an inter-satellite laser link; the second path reconstructs the remote sensing mission command and streaming forwarding configuration parameters into an inter-satellite operation command frame, which is sent out as soon as the laser link is locked.

[0033] Step 3: During the laser link handshake establishment phase, the relay satellite and the target satellite synchronously transmit the inter-satellite operation command frame to the target satellite through the link control frame; the moment the laser link completes scanning, acquisition and locking, the target satellite has synchronously completed the remote sensing mission analysis, without the need for secondary command interaction, and immediately starts the visible light remote sensing payload to carry out imaging operations in the target area, realizing the synchronous start of link establishment and remote sensing operations.

[0034] Step 4: The relay satellite has an independent onboard direct relay unit built in. This unit bypasses the conventional storage controller of the large-capacity onboard storage throughout the entire process, and builds a hardware direct path from laser reception and protocol conversion to microwave transmission.

[0035] The onboard direct relay unit includes a laser deframe submodule, a high-speed micro buffer, a backpressure flow control logic unit, and a microwave frame assembly submodule;

[0036] The laser frame deframe submodule is used to strip the laser protocol header, extract valid remote sensing data, and send it to a high-speed micro-buffer for instantaneous peak clipping;

[0037] The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts its transmission rate, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate.

[0038] After rate adaptation, the data is converted into a frame format in real time by the microwave group frame submodule to adapt to the satellite-to-ground microwave link transmission standard and continuously send streaming data fragments to the ground station.

[0039] Step 5: The ground station continuously receives streaming data fragments from the microwave link, completes protocol parsing, data reconstruction, and visualization frame by frame, without waiting for the entire scene data to be transmitted, and finally achieves second-level end-to-end real-time back transmission of remote sensing data for invisible arc segments.

[0040] Furthermore, the remote sensing mission information domain includes the target area's latitude and longitude, imaging mode, and mission priority;

[0041] The link establishment auxiliary information domain includes the satellite attitude prediction angle, laser scanning window, and link preset bandwidth;

[0042] The streaming forwarding control information field includes the pass-through forwarding enable flag, micro-buffer threshold, and backpressure flow control response coefficient.

[0043] Furthermore, the onboard direct relay unit specifically includes: using the laser link data frame payload as the basic fragmentation unit, each fragment sequentially undergoes the following pipeline stages:

[0044] Phase 1 (Reception and Peak Clipping): The laser deframe submodule strips the laser protocol header from each incoming laser link data frame, extracts effective remote sensing data fragments, and sends them to the high-speed micro buffer for instantaneous peak clipping, absorbing the instantaneous rate difference between the laser link burst rate and the microwave link transmission rate.

[0045] Phase 2 (rate closed-loop control): The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts the transmission rate of remote sensing data of the target satellite, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate.

[0046] Phase 3 (Protocol Transcoding and Distribution): After rate adaptation, the data fragments dequeued from the micro buffer are converted from laser protocol frames to microwave protocol frames in real time by the microwave frame grouping submodule, adapting to the satellite-to-ground microwave link transmission standard, and continuously distributing streaming data fragments to the ground station.

[0047] The three stages described above operate in parallel in a pipeline manner: when the Nth fragment is in the transcoding and transmission stage three, the N+1th fragment is simultaneously in the reception and peak clipping stage one, and the transmission rate of the N+2th fragment is simultaneously adjusted by the back pressure flow control closed loop of stage two. Thus, without relying on large-capacity storage, it achieves non-stacking, non-interruption, and zero-wait streaming data forwarding that simultaneously receives, adapts, transcodes, and transmits.

[0048] Thirdly, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, it performs the steps of the inter-satellite collaborative real-time remote sensing method described above.

[0049] Fourthly, the present invention provides a computer-readable storage medium for storing a computer program that executes an inter-satellite collaborative real-time remote sensing method as described above.

[0050] The beneficial effects of this invention are:

[0051] This invention breaks the industry's inherent technical understanding that "spaceborne cross-system forwarding must rely on large-capacity fixed-line cache." Under the premise of zero storage and zero waiting time, it simultaneously achieves heterogeneous link bandwidth adaptation, sub-millisecond ultra-low forwarding latency, and no interruption or data backlog, breaking through the latency bottleneck of the traditional store-and-forward architecture.

[0052] (1) This invention constructs an integrated composite command triggering mechanism to realize the parallel linkage of task issuance, link establishment, and remote sensing operations. For this mechanism, this invention deploys a joint task command parser in the on-board processing unit of the relay satellite. This parser is a dedicated functional module independent of the traditional telemetry and control parsing module, used to identify and parse the integrated composite command frames issued from the ground. This parser can quickly decompose three types of information: remote sensing task domain, laser link establishment auxiliary domain, and streaming forwarding control domain, and simultaneously output link establishment trigger signal and task forwarding preparation signal, realizing parallel triggering of multiple actions with a single command.

[0053] (2) This invention establishes a bypass direct-through streaming forwarding and dynamic backpressure adaptation mechanism, fundamentally solving the problem of bandwidth mismatch in heterogeneous links and completely abandoning the traditional serial storage-forwarding architecture. Among them, the onboard direct-through forwarding unit is the core hardware bypass module of this invention, which includes a laser deframe submodule, a microwave frame assembly submodule, a high-speed micro-buffer, and a backpressure flow control logic unit. This unit is independent of the conventional data transmission and storage path of the satellite, and can completely bypass the onboard large-capacity fixed storage and its storage controller to build a dedicated high-speed data direct-through link, eliminating storage read and write latency at the hardware level. It is the core component for realizing the joint adaptation of satellite-to-ground microwave and inter-satellite laser heterogeneous links.

[0054] The above mechanism forms a closed-loop collaborative control relationship between the satellite-to-ground microwave link and the inter-satellite laser link. The microwave link carries the downlink transmission of composite commands and bandwidth status feedback, while the laser link carries the high-speed data transmission between satellites and flow control signaling interaction. The two links form a unified joint adaptation system through backpressure flow control logic.

[0055] This invention also provides a rapid link acquisition assistance mechanism. Based on satellite ephemeris data, the ground station predicts the target satellite's spatial position and attitude in real time, generates auxiliary parameters such as the angle acquisition window and scanning range, and encapsulates them into a composite command. The relay satellite, using these auxiliary parameters, optimizes the laser scanning range from a large-angle full-domain scan to a narrow-domain precise scan, significantly shortening the laser link acquisition and locking time.

[0056] This invention is applicable to collaborative real-time remote sensing between two satellites. Attached Figure Description

[0057] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a schematic diagram of the inter-satellite collaborative real-time remote sensing process of the present invention.

[0059] Figure 2 This is a system framework diagram of the inter-satellite collaborative real-time remote sensing of the present invention.

[0060] Figure 3 This is a comparison of the end-to-end task execution timelines of the traditional solution and the solution of this invention. Detailed Implementation

[0061] To address the challenge of real-time acquisition of remote sensing data for hotspot areas, this implementation method employs satellite-to-ground data transmission link communication and inter-satellite laser communication technology to achieve collaborative real-time remote sensing between two satellites. This solves the problem of real-time acquisition of remote sensing data from invisible satellites by satellite ground stations and constructs an inter-satellite collaborative real-time remote sensing system.

[0062] Specific implementation method one, such as Figure 2As shown in this embodiment, an inter-satellite collaborative real-time remote sensing system includes a ground station, a relay satellite A deployed in the same orbit, and a target remote sensing satellite B. Both satellites carry inter-satellite laser communication payloads and satellite-to-ground microwave communication payloads, and have built-in onboard processing units, joint mission command parsers, and onboard direct-pass forwarding units, enabling onboard autonomous command parsing, rapid link establishment, and streaming forwarding capabilities. At a given moment, the operating conditions are as follows: relay satellite A is within the visible arc of the ground station and can stably conduct satellite-to-ground microwave communication; target satellite B is within the invisible arc of the ground station and cannot communicate directly with the ground station, requiring data transmission via relay satellite A. If relay satellite A is currently performing a non-emergency routine mission, upon receiving a composite real-time remote sensing command, it will interrupt its current mission according to command priority and switch to relay collaborative mode.

[0063] The hardware and software functional modules of this embodiment are configured as follows:

[0064] 1. Joint Mission Command Parser. Deployed on the processing unit of Relay Satellite A, this is a dedicated functional module independent of the traditional telemetry, tracking, and command (TT&C) parsing module. It is used to identify and parse integrated composite command frames issued from the ground. This parser can quickly separate three types of information: remote sensing mission domain, laser link establishment assistance domain, and streaming forwarding control domain. It also simultaneously outputs link establishment trigger signals and mission forwarding preparation signals, enabling parallel triggering of multiple actions from a single command.

[0065] 2. Onboard Direct Transmitter Unit. This is the core hardware bypass module in this implementation, comprising a laser deframe submodule, a microwave frame assembly submodule, a high-speed micro-buffer, and a backpressure flow control logic unit. This unit operates independently of the satellite's conventional data transmission and storage path, completely bypassing the onboard high-capacity fixed storage and its storage controller to construct a dedicated high-speed data direct link. It eliminates storage read / write latency at the hardware level and is a core component for achieving joint adaptation between satellite-to-ground microwave and inter-satellite laser heterogeneous links.

[0066] 3. Rapid Link Establishment and Acquisition Assistance Mechanism. Based on satellite ephemeris data, the ground station predicts the spatial position and attitude of target satellite B in real time, generates auxiliary parameters such as angle acquisition window and scanning range, and encapsulates them into composite commands. Relay satellite A, based on these auxiliary parameters, optimizes the laser scanning range from a large-angle full-domain scan to a narrow-domain precise scan, significantly shortening the laser link acquisition and locking time.

[0067] Based on the above modules, the specific implementation steps of this embodiment are as follows:

[0068] Step 1: The ground station generates an integrated, composite, real-time remote sensing command based on the sudden remote sensing needs. The command includes the following: the remote sensing mission information field contains the target area's latitude and longitude, imaging mode, and mission priority; the link establishment assistance information field contains the satellite attitude prediction angle, laser scanning window, and preset link bandwidth; and the streaming forwarding control information field contains the direct forwarding enable flag, micro-buffer threshold, and backpressure flow control response coefficient. The ground station then transmits this composite command to relay satellite A via the satellite-to-ground microwave link.

[0069] Step 2: Relay satellite A completes command parsing through the joint mission command parser and executes two parallel operations simultaneously: The first operation calls the laser communication payload and quickly completes signal acquisition and link locking of target satellite B based on the predicted position and narrow-field scanning parameters; The second operation reconstructs the remote sensing mission and flow control parameters into inter-satellite operation command frames, which are embedded in the control signaling of the laser link establishment process and take effect immediately after the link is locked.

[0070] Step 3: After the inter-satellite laser link is successfully locked, target satellite B has synchronously obtained and resolved the remote sensing operation instructions through the link control signaling. Without additional interaction, the visible light camera is immediately started to carry out push-broom imaging operations, realizing the synchronous start of link establishment and remote sensing operations.

[0071] Step 4: The remote sensing data generated by the target satellite B is encapsulated into laser communication frames in real time and transmitted to relay satellite A via the inter-satellite link. The onboard direct relay unit of relay satellite A takes over, and no data is written to the large-capacity solid-state storage throughout the process.

[0072] The specific process for step 4 is as follows:

[0073] Using the laser link data frame payload as the basic fragmentation unit, the onboard direct-pass forwarding unit performs three processes sequentially on each arriving fragment: reception peak clipping, rate adaptation, and protocol transcoding. First, the laser deframe submodule strips the laser protocol header frame by frame, extracts the effective remote sensing data fragments, and sends them to the high-speed micro-buffer for instantaneous peak clipping to absorb the instantaneous rate difference between the laser link burst rate and the microwave link transmission rate. The micro-buffer only maintains a small number of fragments within the current forwarding window and does not accumulate and store the entire scene data. Next, the backpressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling, and sends it to the target satellite B through the laser link reverse channel to adjust its remote sensing data transmission rate, so that the front-end laser data reception rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate. After the above rate adaptation, the fragments are dequeued from the micro-buffer and the microwave framing submodule performs real-time frame-level transcoding from laser protocol frames to microwave protocol frames to adapt to the satellite-to-ground microwave link transmission standard and continuously transmits them to the ground station. The above three processes are executed concurrently in a pipeline manner. That is, when a certain fragment is in the protocol transcoding and transmission stage, its subsequent fragments are already synchronously performing reception peak clipping. The transmission rate of the subsequent fragments is synchronously adjusted by back pressure flow control closed loop. Thus, without relying on large-capacity storage, it can achieve streaming data forwarding with no backlog, no interruption, and zero waiting time, while receiving, adapting, transcoding, and transmitting simultaneously.

[0074] Step 5: The ground station continuously receives real-time data fragments transmitted via the microwave link, completes protocol parsing, data reassembly, and real-time visualization frame by frame, without waiting for the entire scene data transmission to be completed, achieving instant remote sensing presentation in seconds.

[0075] Step 6: After the remote sensing operation in the target area is completed, the target satellite B transmits the mission completion command back via the laser link. The relay satellite A then closes the direct relay path and the inter-satellite laser link. Both satellites resume their normal on-orbit operation or switch to other missions as needed, waiting for the next scheduling command.

[0076] To overcome the shortcomings of existing technologies, Implementation Method Two, based on the inter-satellite collaborative real-time remote sensing system described above, also provides a joint communication and control method. The system consists of a ground station, a relay satellite A located in the visible arc segment of the ground, and a target remote sensing satellite B located in the invisible arc segment of the ground. The three coordinate to complete delay-free, streaming real-time remote sensing operations.

[0077] Implementation Method 2, such as Figure 1 As shown, an inter-satellite collaborative real-time remote sensing method is implemented through the following steps:

[0078] Step 1: Integrated Generation and Distribution of Composite Real-Time Remote Sensing Commands. The ground station integrates three types of independent information to generate an integrated composite command frame. The command includes a remote sensing mission information domain, an inter-satellite laser rapid link establishment assistance information domain, and a streaming forwarding control information domain, replacing the traditional batch distribution of independent mission commands, link establishment commands, and transmission configuration commands. The command is encapsulated in a single transaction and distributed to relay satellite A via the satellite-to-ground microwave link.

[0079] Step Two: Onboard Command Parsing and Parallel Triggering of Multiple Actions. Relay Satellite A carries a dedicated joint mission command parser to receive and parse composite command frames, simultaneously triggering two parallel actions: The first action extracts laser link establishment auxiliary parameters, completes target satellite position prediction and scan uncertainty area reduction, initiates narrow-range rapid scan acquisition, and quickly establishes an inter-satellite laser link; the second action reconstructs remote sensing mission commands and streaming forwarding configuration parameters into inter-satellite operation command frames, which are then sent out as soon as the laser link is locked.

[0080] Specifically, one action involves extracting laser link establishment auxiliary parameters (i.e., satellite attitude prediction angle, laser scanning window, and link preset bandwidth) from the link establishment auxiliary information domain, completing the target satellite position prediction and narrowing of the scanning uncertainty area, initiating narrow-range rapid scanning acquisition, and establishing an inter-satellite laser link;

[0081] Another action is to reconstruct the remote sensing mission instructions (i.e., target area latitude and longitude, imaging mode and mission priority) corresponding to the remote sensing mission information domain and the streaming forwarding configuration parameters (i.e., pass-through forwarding enable flag, micro-buffer threshold and back pressure flow control response coefficient) corresponding to the streaming forwarding control information domain into an inter-satellite operation instruction frame.

[0082] Specifically, the reconstruction includes:

[0083] The microwave link protocol encapsulation is stripped from the integrated composite command frame, and the payload fields of remote sensing mission commands and streaming forwarding configuration parameters are extracted. The frames are then reassembled according to the inter-satellite laser link control signaling frame format, so that they can be directly embedded in the control signaling frame payload area during the laser link scanning, acquisition, and locking handshake process. Once the laser link is locked, the target satellite can directly parse the complete operation command from the link control signaling without the need to establish an additional upper-layer mission interaction channel.

[0084] Step 3: Link Establishment and Extremely Low-Latency Remote Sensing Initiation. During the laser link handshake establishment phase, relay satellite A and target satellite B synchronously transmit inter-satellite operation command frames to target satellite B via link control frames. The instant the laser link completes scanning, acquisition, and locking, target satellite B has simultaneously completed remote sensing task analysis. Without secondary command interaction, it immediately initiates visible light remote sensing payloads to perform imaging operations on the target area, achieving simultaneous link establishment and remote sensing operation initiation, completely eliminating serial waiting delays.

[0085] Step 4: Real-time streaming collaborative forwarding of heterogeneous links. Relay satellite A has a built-in independent onboard direct forwarding unit. This unit bypasses the conventional storage controller with its large-capacity onboard storage throughout the entire process, constructing a hardware direct path from laser reception to protocol conversion to microwave transmission. Using the laser link data frame payload as the basic fragmentation unit, each arriving fragment undergoes three processing steps in sequence: reception peak clipping, rate adaptation, and protocol transcoding. First, the laser protocol header is stripped frame by frame from the laser link data frames using an on-chip micro-buffer. Effective remote sensing data fragments are extracted and sent to a high-speed micro-buffer for instantaneous peak clipping, absorbing the instantaneous rate difference between the laser link burst rate and the microwave link transmission rate. Then, the available bandwidth of the satellite-to-ground microwave link is collected in real time through dynamic backpressure flow control logic, and flow control signals are sent to target satellite B via the laser link reverse channel to adjust its remote sensing data transmission rate, forming a closed-loop control of the inter-satellite laser link transmission rate based on the satellite-to-ground microwave link bandwidth status. After the above rate adaptation, the fragments are dequeued from the micro-buffer, completing frame-level real-time transcoding from laser protocol frames to microwave protocol frames, adapting to the satellite-to-ground microwave link transmission standard, and continuously sending streaming data fragments to the ground station. The above three processes are executed concurrently in a pipeline manner. That is, when a certain segment is in the protocol transcoding and transmission stage, its subsequent segments are already synchronously performing reception peak clipping. The transmission rate of the subsequent segments is synchronously adjusted by back pressure flow control closed loop. Thus, without relying on large-capacity storage, the rate of high-speed laser data stream and low-speed microwave downlink can be smoothly adapted, achieving streaming data forwarding with no backlog, no interruption, and zero waiting time while receiving, adapting, transcoding, and transmitting.

[0086] Step 5: Real-time analysis and instant data presentation by the ground station. The ground station continuously receives streaming data fragments from the microwave link, completes protocol analysis, data reconstruction, and visualization frame by frame, without waiting for the entire scene to be transmitted, ultimately achieving second-level end-to-end instant backhaul of remote sensing data for invisible arc segments.

[0087] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0088] A certain low-Earth orbit remote sensing satellite constellation consists of 12 high-resolution optical remote sensing satellites at an orbital altitude of approximately 550 km. Only two ground-based tracking and control stations are deployed, with each station having less than 5% visibility of a single satellite's orbit. By employing the inter-satellite collaborative real-time remote sensing system of this invention, three relay satellites are deployed in the same orbital plane. Each relay satellite carries a joint mission command parser and an onboard direct-transfer unit, possessing onboard autonomous command parsing, rapid link establishment, and streaming forwarding capabilities. Taking a flood disaster emergency remote sensing mission as an example, the specific operational process is as follows:

[0089] (1) When the ground station receives the emergency disaster reduction department’s real-time remote sensing requirements for the target area, the operation terminal automatically integrates and generates an integrated composite command frame based on the latitude and longitude of the target area, imaging mode and task priority. The frame contains remote sensing task information domain, link establishment auxiliary information domain and streaming forwarding control information domain. It is sent to relay satellite A in the visible arc in a single delivery via the satellite-ground microwave link, replacing the traditional mode of issuing three types of commands in batches.

[0090] (2) After receiving the composite command frame, the joint mission command parser of relay satellite A synchronously triggers two parallel actions: one extracts the link establishment auxiliary parameters and uses the ephemeris to predict the attitude angle of the target satellite B to compress the laser scanning range from the conventional ±15° full-domain scanning to the ±1.8° narrow-domain scanning, and completes the scanning, acquisition and locking of the laser link within 220ms; the other extracts the remote sensing mission command and streaming forwarding configuration parameters from the microwave protocol encapsulation, re-frames them into an inter-satellite operation command frame, embeds it in the control signaling of the laser link handshake process, and sends it to the target satellite B immediately after the link is locked.

[0091] (3) While the laser link is locked, the target satellite B has synchronously parsed the complete remote sensing operation instructions from the control signaling. There is no need for the ground station to issue the instructions again. The on-board processing unit immediately starts the multispectral camera to carry out push-broom imaging of the target area, realizing the synchronous start of link establishment and remote sensing operation, and completely eliminating the serial waiting delay between link establishment and task instructions in the traditional scheme.

[0092] (4) Remote sensing data generated during the imaging process of target satellite B is transmitted to relay satellite A in real time via laser communication frames. The onboard direct relay unit of relay satellite A bypasses the onboard large-capacity fixed storage throughout the process and performs pipeline processing in units of data fragments: the laser deframe submodule strips the protocol header frame by frame to extract data fragments, and after instantaneous peak reduction by micro-buffer, the back pressure flow control logic dynamically adjusts the transmission rate of target satellite B through the laser reverse channel according to the available bandwidth of the microwave link monitored in real time, so that the front-end laser reception and the back-end microwave transmission rate are matched; after the rate adaptation, the fragments are converted into the frame format in real time by the microwave frame assembly submodule and continuously transmitted to the ground station;

[0093] (5) The ground station continuously receives streaming data fragments from the microwave link, parses them frame by frame and splices them together in real time without waiting for the entire scene data to be transmitted, thus realizing the instant presentation of remote sensing data of invisible arc segments.

[0094] In this embodiment, the measured end-to-end arrival latency of the first frame of remote sensing data was 510ms, while under the same conditions, the latency of the first frame of the traditional store-and-forward scheme was greater than 6s, representing a latency reduction of over 90%. The onboard storage requirement was reduced from several GB in the traditional scheme to 64MB, relying solely on micro-buffering for instantaneous peak shaving. Under conditions of dynamic fluctuations in microwave link bandwidth, the backpressure flow control closed loop effectively maintained the matching of transmit and receive rates, preventing packet loss due to buffer overflow. These results verify the effectiveness and engineering feasibility of this invention in emergency real-time remote sensing scenarios.

[0095] Simulation verification:

[0096] To verify the technical effectiveness of the present invention, a simulation comparison experiment of an inter-satellite collaborative real-time remote sensing system was designed. The simulation time step was set to 50 μs, and the total simulation duration was 40 s. The details of the specific simulation parameters are shown in Table 1.

[0097] Table 1 Simulation Parameter Settings

[0098] Shared link and data parameters Traditional scheme parameters Parameters of the present invention Inter-satellite laser link bandwidth: 5 Gbps Task command issuance duration: 100 ms Task command issuance duration: 30 ms Satellite-to-ground microwave link bandwidth: 500 Mbps Inter-satellite link establishment time: 800 ms Inter-satellite link establishment time: 220 ms Total remote sensing data: 2 GB Command interaction time after link establishment: 50 ms Command interaction time after chain establishment: 0 Push-broom imaging time: 2 s Relay Star Cache: Large-Capacity Fixed Storage Relay satellite cache: 64 MB micro-cache

[0099] In the simulation experiment, the two schemes were subjected to full-process numerical simulation under the same task scenario: the traditional scheme was modeled as serial issuance of task instructions, full-domain scanning and link establishment, secondary instruction interaction, imaging and whole-scene storage, and store-and-forward to the ground, executed sequentially; the scheme of this invention was modeled as integrated composite instruction issuance, parallel narrow-domain link establishment and instruction reconstruction, and link establishment as a job and pipeline direct forwarding. The performance differences between the two schemes were compared in three aspects: end-to-end latency, relay satellite buffer usage, and rate matching under dynamic bandwidth.

[0100] Simulation Result Analysis:

[0101] Based on the above parameters and simulation results, the performance indicators of the two schemes are compared as shown in Table 2.

[0102] Table 2 Comparison of Simulation Results

[0103] Performance indicators Traditional solution Invention Solution First frame of remote sensing data ground arrival time 2950 ms 250 ms Overall completion time for a single task 35.34 s 32.93 s Relay satellite peak cache usage 2.00 GB 0.02 MB

[0104] Figure 3This paper compares the end-to-end task execution timelines of the traditional solution and the solution of this invention. In the traditional solution, the four stages of instruction issuance (100 ms), full-domain scanning and link establishment (800 ms), secondary instruction interaction (50 ms), and imaging and whole-scene storage (2000 ms) are executed sequentially, resulting in a cumulative invalid waiting delay of approximately 2.95 s. Forwarding only begins after all whole-scene data has been stored. The solution of this invention, through an integrated composite instruction frame and a link establishment-as-work mechanism, compresses the link establishment scanning range from ±15° to ±1.8° (reducing the link establishment time from 800 ms to 220 ms). Simultaneously, link establishment and instruction reconstruction are processed in parallel, and the job and streaming pass-through forwarding are started synchronously the moment the link is locked. The process is simplified to two stages: composite instruction issuance and narrow-domain link establishment. The first frame latency is only 250 ms, which is 91.5% lower than the traditional solution.

[0105] Table 2 also shows that, in terms of cache usage, the relay star peak cache in this invention is only 0.02 MB, while the traditional solution requires 2.00 GB of fixed storage. This difference stems from the direct-forward architecture where the onboard direct-forward unit bypasses the fixed storage throughout the entire process, using only a micro-cache for instantaneous peak reduction. Regarding dynamic bandwidth, under conditions where the satellite-to-ground microwave link fluctuates at an average of 500 Mbps with a ±30% amplitude, the backpressure flow control closed-loop of this invention dynamically matches the transmit and receive rates, preventing any buffer overflow or packet loss throughout the process.

Claims

1. An inter-satellite collaborative real-time remote sensing system, the system comprising a ground station, a relay satellite located in a visible arc segment of the ground, and a target remote sensing satellite located in an invisible arc segment of the ground, characterized in that, The ground station generates an integrated composite command frame and sends it to the relay satellite. The composite command includes a remote sensing mission information domain, an inter-satellite laser rapid link establishment auxiliary information domain, and a streaming forwarding control information domain. The relay satellite carries a dedicated joint mission command parser for receiving and parsing composite command frames; After locking onto the inter-satellite laser link, the target satellite receives remote sensing operation instructions and begins operations; The relay satellite has an independent onboard direct relay unit, which includes a laser frame de-framing submodule, a high-speed micro buffer, a backpressure flow control logic unit, and a microwave frame assembly submodule. The laser frame deframe submodule is used to strip the laser protocol header, extract valid remote sensing data, and send it to a high-speed micro-buffer for instantaneous peak clipping; The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts its transmission rate, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate. After rate adaptation, the data undergoes real-time frame format conversion by the microwave group frame submodule to adapt to the satellite-to-ground microwave link transmission standard and continuously sends streaming data fragments to the ground station.

2. The inter-satellite collaborative real-time remote sensing system according to claim 1, characterized in that: The remote sensing mission information domain includes the target area's latitude and longitude, imaging mode, and mission priority; The link establishment auxiliary information domain includes the satellite attitude prediction angle, laser scanning window, and link preset bandwidth; The streaming forwarding control information field includes the pass-through forwarding enable flag, micro-buffer threshold, and backpressure flow control response coefficient.

3. The inter-satellite collaborative real-time remote sensing system according to claim 2, characterized in that: After receiving the integrated composite instruction frame, the joint task instruction parser synchronously triggers two parallel actions: One action is to extract laser link establishment auxiliary parameters from the link establishment auxiliary information domain, complete the target satellite position prediction and the reduction of the scanning uncertainty area, start narrow-range rapid scanning acquisition, and establish an inter-satellite laser link; Another action involves reconstructing the remote sensing mission instructions corresponding to the remote sensing mission information domain and the streaming forwarding configuration parameters corresponding to the streaming forwarding control information domain into an inter-satellite operation instruction frame. Specifically, this reconstruction includes: The microwave link protocol encapsulation is stripped from the integrated composite command frame, and the payload fields of remote sensing mission commands and streaming forwarding configuration parameters are extracted. The frames are then reassembled according to the inter-satellite laser link control signaling frame format so that they can be directly embedded in the control signaling frame payload area during the laser link scanning, acquisition, and lock handshake process. Once the laser link is locked, the target satellite can directly parse the complete operational instructions from the link control signaling without the need to establish an additional upper-level mission interaction channel.

4. The inter-satellite collaborative real-time remote sensing system according to claim 3, characterized in that: The onboard direct relay unit specifically includes: Using the laser link data frame payload as the basic unit of segmentation, each segment sequentially undergoes the following pipeline stages: Phase 1: The laser frame de-framing submodule strips the laser protocol header from each incoming laser link data frame, extracts effective remote sensing data fragments, and sends them to the high-speed micro buffer for instantaneous peak clipping, absorbing the instantaneous rate difference between the laser link burst rate and the microwave link transmission rate. Phase 2: The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts the transmission rate of remote sensing data of the target satellite, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate. Phase 3: After rate adaptation, the data fragments dequeued from the micro buffer are converted from laser protocol frames to microwave protocol frames in real time by the microwave frame grouping submodule, adapting to the satellite-to-ground microwave link transmission standard, and continuously sending streaming data fragments to the ground station. The three stages described above operate in parallel in a pipeline manner: when the Nth fragment is in the transcoding and transmission stage three, the N+1th fragment is simultaneously in the reception and peak clipping stage one, and the transmission rate of the N+2th fragment is simultaneously adjusted by the back pressure flow control closed loop of stage two. Thus, without relying on large-capacity storage, it achieves non-stacking, non-interruption, and zero-wait streaming data forwarding that simultaneously receives, adapts, transcodes, and transmits.

5. The inter-satellite collaborative real-time remote sensing system according to claim 1, characterized in that: Both the relay satellite and the target remote sensing satellite are equipped with inter-satellite laser communication payloads and satellite-to-ground microwave communication payloads, and have built-in on-board processing units, joint mission command parsers, and on-board direct forwarding units, enabling them to perform on-board autonomous command parsing, rapid link establishment, and streaming forwarding capabilities.

6. An inter-satellite collaborative real-time remote sensing method based on the inter-satellite collaborative real-time remote sensing system according to any one of claims 1-5, characterized in that, The method includes: Step 1: The ground station integrates three types of independent information to generate an integrated composite command frame. This command frame includes a remote sensing mission information domain, an inter-satellite laser rapid link establishment auxiliary information domain, and a streaming forwarding control information domain. The command is encapsulated in a single operation and sent to the relay satellite via the satellite-to-ground microwave link. Step 2: The relay satellite carries a joint mission command parser to receive and parse composite command frames, simultaneously triggering two parallel actions: the first path extracts laser link establishment auxiliary parameters, completes the prediction of the target satellite's position and the reduction of the scanning uncertainty area, starts narrow-range rapid scanning and acquisition, and quickly establishes an inter-satellite laser link; the second path reconstructs the remote sensing mission command and streaming forwarding configuration parameters into an inter-satellite operation command frame, which is sent out as soon as the laser link is locked. Step 3: During the laser link handshake establishment phase, the relay satellite and the target satellite synchronously transmit the inter-satellite operation command frame to the target satellite through the link control frame; the moment the laser link completes scanning, acquisition and locking, the target satellite has synchronously completed the remote sensing mission analysis, without the need for secondary command interaction, and immediately starts the visible light remote sensing payload to carry out imaging operations in the target area, realizing the synchronous start of link establishment and remote sensing operations. Step 4: The relay satellite has an independent onboard direct relay unit built in. This unit bypasses the conventional storage controller of the large-capacity onboard storage throughout the entire process, and builds a hardware direct path from laser reception and protocol conversion to microwave transmission. The onboard direct relay unit includes a laser deframe submodule, a high-speed micro buffer, a backpressure flow control logic unit, and a microwave frame assembly submodule; The laser frame deframe submodule is used to strip the laser protocol header, extract valid remote sensing data, and send it to a high-speed micro-buffer for instantaneous peak clipping; The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts its transmission rate, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate. After rate adaptation, the data is converted into a frame format in real time by the microwave group frame submodule to adapt to the satellite-to-ground microwave link transmission standard and continuously send streaming data fragments to the ground station. Step 5: The ground station continuously receives streaming data fragments from the microwave link, completes protocol parsing, data reconstruction, and visualization frame by frame, without waiting for the entire scene data to be transmitted, and finally achieves second-level end-to-end real-time back transmission of remote sensing data for invisible arc segments.

7. The inter-satellite collaborative real-time remote sensing method according to claim 6, characterized in that: The remote sensing mission information domain includes the target area's latitude and longitude, imaging mode, and mission priority; The link establishment auxiliary information domain includes the satellite attitude prediction angle, laser scanning window, and link preset bandwidth; The streaming forwarding control information field includes the pass-through forwarding enable flag, micro-buffer threshold, and backpressure flow control response coefficient.

8. The inter-satellite collaborative real-time remote sensing method according to claim 6, characterized in that: The onboard direct relay unit specifically includes: Using the laser link data frame payload as the basic unit of segmentation, each segment sequentially undergoes the following pipeline stages: Phase 1: The laser frame de-framing submodule strips the laser protocol header from each incoming laser link data frame, extracts effective remote sensing data fragments, and sends them to the high-speed micro buffer for instantaneous peak clipping, absorbing the instantaneous rate difference between the laser link burst rate and the microwave link transmission rate. Phase 2: The back pressure flow control logic unit monitors the available bandwidth of the satellite-to-ground microwave link in real time, dynamically generates flow control signaling and sends it to the target satellite through the reverse channel of the laser link, adjusts the transmission rate of remote sensing data of the target satellite, so that the front-end laser data receiving rate and the back-end microwave downlink transmission rate are dynamically matched, forming a closed-loop adaptive control of the microwave link bandwidth status on the laser link data rate. Phase 3: After rate adaptation, the data fragments dequeued from the micro buffer are converted from laser protocol frames to microwave protocol frames in real time by the microwave frame grouping submodule, adapting to the satellite-to-ground microwave link transmission standard, and continuously sending streaming data fragments to the ground station. The three stages described above operate in parallel in a pipeline manner: when the Nth fragment is in the transcoding and transmission stage three, the N+1th fragment is simultaneously in the reception and peak clipping stage one, and the transmission rate of the N+2th fragment is simultaneously adjusted by the back pressure flow control closed loop of stage two. Thus, without relying on large-capacity storage, it achieves non-stacking, non-interruption, and zero-wait streaming data forwarding that simultaneously receives, adapts, transcodes, and transmits.

9. A computer device, characterized in that: It includes a memory and a processor, wherein the memory stores a computer program, and when the processor runs the computer program stored in the memory, it performs the steps of the inter-satellite collaborative real-time remote sensing method according to any one of claims 6-8.

10. A computer-readable storage medium, characterized in that: The storage medium is used to store a computer program that executes an inter-satellite collaborative real-time remote sensing method according to any one of claims 6-8.

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