Satellite-borne AIS guided SAR load multi-target same-side time sequence optimization imaging method

Abstract

The invention provides a satellite-borne AIS (Automatic Identification System) guided SAR (Synthetic Aperture Radar) load multi-target same-side time sequence optimization imaging method. The method comprises the following steps: acquiring observation information of a plurality of candidate targets; based on a satellite body coordinate system, same-side candidate targets which are located on the same side of a satellite and conform to side view angle constraints are screened out, target imaging windows are predicted based on observation information of the candidate targets and satellite orbit parameters, and at least two to-be-imaged targets are determined according to window continuity and total duration constraints; according to the method, a unified time sequence task sequence is generated according to SAR load parameters and target information, when the sequence is executed, continuous imaging is performed at a fixed side view angle, the SAR load working state is adaptively controlled according to an imaging interval, and the load is closed and the satellite attitude is recovered after imaging is finished, so that multi-target conflict-free continuous imaging is realized, the imaging efficiency and the window capture rate are improved, and the imaging quality is improved. And satellite resources and energy are saved.

Description

Technical Field

[0001] This invention relates to the field of remote sensing SAR satellite imaging technology, and in particular to a multi-target simultaneous temporal optimization imaging method for a spaceborne AIS-guided SAR payload. Background Technology

[0002] In the field of maritime ship monitoring, SAR satellites have become an important technical means due to their all-day, all-weather imaging capabilities.

[0003] Existing spaceborne AIS-guided SAR imaging technology suffers from significant deficiencies in multi-target processing capabilities: it can only select the highest-priority single target from multiple detected targets for imaging tasks at a time, and must reselect targets and plan tasks after the target is imaged before starting the next imaging session. This results in extremely low imaging efficiency in multi-target scenarios and an inability to simultaneously respond to the imaging needs of multiple high-value targets. The process of reselecting targets and replanning tasks between two imaging sessions introduces additional time delays, which can easily lead to missed opportunities for effective imaging of targets with high speeds or short imaging windows. When multiple targets on the same side exist within the same field of view, they still need to be imaged one by one and the attitude maneuvering and task planning processes need to be repeated. This not only consumes a large amount of onboard computing resources but also significantly consumes onboard energy due to frequent attitude adjustments, severely restricting the application effectiveness of SAR satellites in multi-target ship monitoring scenarios.

[0004] Therefore, how to achieve conflict-free continuous imaging of multiple targets, improve imaging efficiency and imaging window capture rate, and save on-board computing resources and energy are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a multi-target simultaneous temporal optimization imaging method for spaceborne AIS-guided SAR payloads, which can achieve collision-free continuous imaging of multiple targets, improve imaging efficiency and imaging window capture rate, and save on-board computing resources and energy.

[0006] On one hand, the present invention provides a multi-target simultaneous temporal optimization imaging method for a spaceborne AIS-guided SAR payload, comprising: Acquire observation information of multiple candidate targets; the observation information includes pose information and priority information; Based on the satellite body coordinate system, targets located on the same side of the satellite and whose lateral distance meets the preset side-view angle constraint are selected from the multiple candidate targets and used as same-side candidate targets; Based on the observation information and satellite orbit parameters of each target in the same-side candidate targets, the imaging window of each target is predicted, and according to the continuity of the imaging window and the preset total imaging duration constraint, at least two targets to be imaged for continuous imaging are determined from the same-side candidate targets. Based on the inherent operating parameters of the SAR payload and the observation information of each target to be imaged, a unified time-series task sequence containing the imaging operations and time nodes of all targets to be imaged is generated. The unified time-sequential task sequence is executed to continuously image at least two targets to be imaged from a fixed side-view angle. During the continuous imaging process, the working state of the SAR payload is adaptively controlled according to the imaging interval. After the imaging of the last target to be imaged is completed, the SAR payload is powered off and the satellite attitude is restored.

[0007] On the other hand, the present invention also provides a multi-target simultaneous temporal optimization imaging system for a spaceborne AIS-guided SAR payload, comprising: An acquisition module is used to acquire observation information of multiple candidate targets; the observation information includes pose information and priority information. The filtering module is used to filter out targets located on the same side of the satellite and whose lateral distance meets the preset side-view angle constraint from the multiple candidate targets based on the satellite body coordinate system, and to select them as same-side candidate targets. The prediction module is used to predict the imaging window of each target based on the observation information and satellite orbit parameters of each target in the same-side candidate targets, and to determine at least two targets to be imaged from the same-side candidate targets for continuous imaging according to the continuity of the imaging window and the preset total imaging duration constraint. The generation module is used to generate a unified time-series task sequence containing imaging operations and time nodes for all targets to be imaged, based on the inherent operating parameters of the SAR payload and the observation information of each target to be imaged. The execution module is used to execute the unified time-sequential task sequence, continuously image the at least two targets to be imaged at a fixed side-view angle, adaptively control the working state of the SAR payload according to the imaging interval during the continuous imaging process, and control the SAR payload to shut down and the satellite attitude to be restored after the imaging of the last target to be imaged is completed.

[0008] The present invention provides a multi-target same-side time-series optimized imaging method for spaceborne AIS-guided SAR payloads. This method acquires observation information of multiple candidate targets and filters out same-side candidate targets located on the same side of the satellite with lateral distances satisfying preset side-looking angle constraints based on the satellite's body coordinate system. It then predicts imaging windows by combining target motion states and satellite orbital parameters, and determines at least two targets to be imaged based on window continuity and total imaging duration constraints. A unified time-series task sequence containing imaging operations and time nodes for all targets to be imaged is generated based on the SAR payload's inherent operating parameters and target observation information. This sequence is executed for continuous imaging at a fixed side-looking angle. The SAR payload's operating state is adaptively controlled according to the imaging interval, and the payload is powered off and the satellite's attitude is restored after imaging is completed. Simultaneously, the imaging data is classified and differentially transmitted back, achieving conflict-free continuous imaging of multiple targets, improving imaging efficiency and imaging window capture rate, and saving onboard computing resources and energy. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0010] Figure 1 This is a flowchart illustrating the multi-target simultaneous temporal optimization imaging method for spaceborne AIS-guided SAR payloads provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the multi-target simultaneous temporal optimization imaging system of the spaceborne AIS-guided SAR payload provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0012] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0013] Figure 1 This is a flowchart illustrating the multi-target simultaneous temporal optimization imaging method for spaceborne AIS-guided SAR payloads provided in an embodiment of the present invention.

[0014] like Figure 1 As shown in the embodiments of the present invention, the multi-target same-side time-series optimized imaging method for spaceborne AIS-guided SAR payloads mainly includes the following steps: 101. Obtain observation information of multiple candidate targets; the observation information includes pose information and priority information; 102. Based on the satellite body coordinate system, select targets located on the same side of the satellite and whose lateral distance meets the preset side-view angle constraint from the multiple candidate targets, and use them as same-side candidate targets; 103. Based on the observation information and satellite orbit parameters of each target in the same-side candidate targets, predict the imaging window of each target, and determine at least two targets to be imaged for continuous imaging from the same-side candidate targets according to the continuity of the imaging window and the preset total imaging duration constraint. 104. Based on the inherent operating parameters of the SAR payload and the observation information of each target to be imaged, generate a unified time-seriesd task sequence that includes the imaging operations and time nodes of all targets to be imaged. 105. Execute the unified time-sequential task sequence to continuously image the at least two targets to be imaged at a fixed side-view angle, and adaptively control the working state of the SAR payload according to the imaging interval during the continuous imaging process, and control the SAR payload to shut down and the satellite attitude to be restored after the imaging of the last target to be imaged is completed.

[0015] In a specific implementation process, a spaceborne AIS receiver can be used to continuously receive ship AIS signals. After demodulation and decoding, the pose information of multiple candidate targets (such as real-time position coordinates, speed, heading, etc.) and priority information recorded on the ground can be extracted to provide basic data for subsequent target selection and planning.

[0016] After obtaining observation information for multiple candidate targets, based on a preset satellite coordinate system, coordinate transformation and distance calculation can be used to filter out candidate targets located on the same side of the satellite and whose lateral distance meets the fixed side-looking angle requirements. This ensures that the targets are compatible with the imaging view range of the SAR payload and avoids imaging failure due to mismatched target positions. Then, combining the motion state of the candidate targets on the same side with the satellite orbital parameters, the imaging window for each target is predicted through a kinematic model. The continuity of the window is judged, and combined with the total imaging duration constraint, at least two targets without time conflicts are selected for imaging. This ensures that high-value targets are prioritized for imaging while also adapting to the limitations of satellite on-orbit resources.

[0017] After obtaining the target to be imaged, the satellite attitude parameters and payload imaging parameters can be calculated based on the inherent operating parameters of the SAR payload (such as strip mode, fixed side-looking angle, etc.) and the observation information of each target to be imaged. These parameters are then associated with key time nodes such as attitude maneuver initiation, imaging warm-up, imaging start and end, and attitude recovery to generate a unified time-series task sequence, avoiding delays caused by multiple replanning.

[0018] Finally, imaging operations are executed according to the mission sequence: attitude adjustment and payload warm-up are completed before imaging the first target; subsequent imaging continues while maintaining the same attitude; the payload is dynamically controlled to be in standby or powered off based on the imaging interval of adjacent targets; after imaging the last target, the payload is turned off and the satellite's normal Earth-orientation attitude is restored, ensuring that the imaging process is efficient, energy-saving, and does not affect subsequent satellite missions. Among these, target observation information acquisition and same-side target selection are fundamental, imaging window prediction and target determination are core, and the generation and execution of a unified temporal mission sequence is key to ensuring efficient multi-target imaging.

[0019] This embodiment presents a multi-target same-side time-series optimized imaging method for spaceborne AIS-guided SAR payloads. By acquiring observation information of multiple candidate targets, it filters out same-side candidate targets located on the same side of the satellite and whose lateral distances meet preset side-looking angle constraints based on the satellite's body coordinate system. Combining target motion states and satellite orbital parameters, it predicts imaging windows and determines at least two targets to be imaged based on window continuity and total imaging duration constraints. A unified time-series task sequence containing imaging operations and time nodes for all targets to be imaged is generated based on the SAR payload's inherent operating parameters and target observation information. This sequence is executed for continuous imaging at a fixed side-looking angle. The SAR payload's operating state is adaptively controlled according to the imaging interval, and the payload is powered off and the satellite's attitude is restored after imaging is complete. Simultaneously, the imaging data is classified and differentially transmitted back. This achieves conflict-free continuous imaging of multiple targets, improves imaging efficiency and imaging window capture rate, and saves onboard computing resources and energy.

[0020] In some embodiments, the process of screening candidate targets on the same side may include: Establish a satellite body coordinate system with the satellite's center of mass as the origin, the first axis (X-axis) along the flight direction, the second axis (Y-axis) perpendicular to the orbital plane and outward, and the third axis (Z-axis) pointing towards the Earth's center; The position coordinates of each candidate target are transformed to the satellite body coordinate system, and the Y-axis coordinate and lateral distance relative to the nadir point of each candidate target are calculated. Targets with the same Y-axis coordinate sign and a lateral distance less than or equal to a preset distance threshold are selected as candidate targets on the same side.

[0021] Specifically, to accurately determine the relative position of the target and the satellite, a standardized satellite coordinate system can be established: with the satellite's center of mass as the origin, the coordinate axes are defined as follows: the X-axis along the flight direction, the Y-axis perpendicular to the orbital plane and outward, and the Z-axis pointing towards the Earth's center. This coordinate system can intuitively reflect the target's lateral position relative to the satellite.

[0022] After establishing the satellite's coordinate system, the original position coordinates of each candidate target can be transformed to this coordinate system to eliminate positional deviations caused by different coordinate systems and ensure the accuracy of subsequent calculations. At the same time, the Y-axis coordinate and lateral distance relative to the nadir point of each target are calculated. The Y-axis coordinate sign directly indicates whether the target is located to the left or right of the satellite, while the lateral distance reflects the horizontal distance of the target from the nadir point.

[0023] After the above operations, targets can be selected according to the filtering conditions: consistent Y-axis coordinate signs mean that the targets are located on the same side of the satellite, which meets the spatial basis for continuous imaging; the lateral distance is less than or equal to the preset distance threshold, which ensures that the targets are within the effective coverage range of the fixed side-looking angle of the SAR payload, avoiding poor imaging quality due to excessive distance.

[0024] It should be noted that the preset distance threshold is determined based on the track height and a fixed side-view angle.

[0025] Specifically, the preset distance threshold is calculated geometrically based on the satellite's current orbital altitude and the SAR payload's fixed side-look angle (e.g., 30°). For example, the lateral distance threshold is equal to the orbital altitude multiplied by the tangent of the fixed side-look angle. This threshold ensures that all selected targets are within the imaging coverage area of ​​the SAR payload.

[0026] In this embodiment, based on the geometric constraints of satellite imaging, imageable targets on the same side are quickly locked, providing an accurate input set for subsequent multi-target continuous imaging, reducing interference from invalid targets, and improving the targeting and efficiency of mission planning.

[0027] In some embodiments, the process of determining at least two targets to be imaged for sequential imaging may include: Based on the motion state and satellite orbit parameters of each candidate target on the same side, the time when each candidate target enters and leaves the SAR imaging coverage area is predicted by the kinematic model, thus obtaining the start and end times of the imaging window; Calculate the imaging time for each candidate target on the same side; Sort all candidate targets on the same side in order of distance from the satellite's nadir point, from closest to furthest. Determine whether the start time of the next target in the imaging window of adjacent targets after sorting is greater than or equal to the end time of the previous target. Calculate the sum of the imaging times of consecutive targets within the imaging window; Based on the priority information, at least two targets whose sum of imaging time does not exceed a preset total duration limit are selected as the targets to be imaged.

[0028] Specifically, based on the selected candidate targets on the same side, and combined with the motion state of each target (such as speed and heading) and satellite orbital parameters, the relative motion process between the target and the satellite can be simulated through a kinematic model. The start time of each target entering the SAR imaging coverage and the end time of its departure can be predicted. The two constitute the imaging window of the target. At the same time, the imaging time of a single target (the difference between the end time and the start time) can be calculated.

[0029] Next, targets are sorted in order of distance from the satellite's nadir point, from closest to furthest. This sorting method conforms to the spatial logic of satellite flight and imaging, facilitating the assessment of the feasibility of imaging continuations for adjacent targets. Then, it is determined whether the imaging windows of adjacent targets are continuous after sorting, i.e., the start time of the subsequent target is no earlier than the end time of the previous target, ensuring no time overlap or conflict in imaging adjacent targets. Then, the total imaging time is calculated from targets with continuous imaging windows. Combined with target priority information, at least two targets whose total imaging time does not exceed the preset total duration limit are selected as targets to be imaged. This satisfies the multi-target imaging requirement while adapting to satellite on-orbit resource constraints. In this process, imaging window prediction is the basis for assessing the feasibility of continuous imaging, window continuity assessment is key to avoiding timing conflicts, and the selection of priorities and duration constraints is the core of balancing imaging requirements and resource limitations.

[0030] It should be noted that if the sum of the imaging times exceeds the preset total duration limit, targets are eliminated in descending order of priority or in descending order of imaging time, until the sum of the imaging times does not exceed the preset total duration limit. In other words, if the total imaging time of consecutive targets within the selected imaging window exceeds the preset total duration limit, it indicates that the current target set exceeds the satellite's on-orbit resource carrying capacity, and targets need to be eliminated using a reasonable strategy. Two elimination logics can be adopted: one is to sort by priority from high to low, eliminating lower-priority targets first to ensure high-value targets are retained; the other is to sort by imaging time from long to short, eliminating targets with the longest imaging time first to quickly reduce the total imaging time. During the elimination process, the total imaging time of the remaining targets is calculated in real time after each elimination until the total time does not exceed the preset limit, ultimately determining the set of targets to be imaged that meets the requirements.

[0031] This embodiment ensures seamless connection of multiple target imaging windows and controllability of total duration by using timing conflict judgment and duration constraints, avoiding imaging conflicts and timeout risks, and improving the executability and timeliness of the task.

[0032] In some embodiments, the process of generating a unified time-series task sequence that includes imaging operations and time points for all targets to be imaged may include: Based on the inherent operating parameters of the SAR payload and the observation information of each target to be imaged, the satellite attitude parameters and SAR payload imaging parameters are calculated. The satellite attitude parameters and the SAR payload imaging parameters are correlated with the first attitude maneuver start time, the first imaging warm-up time, the imaging start and end times of each target to be imaged, and the attitude recovery time. This forms a chronological sequence of tasks that includes imaging operations for all targets to be imaged.

[0033] Specifically, satellite attitude parameters (such as attitude angles adapted to fixed side-looking angles) and SAR payload imaging parameters (such as imaging bandwidth, pulse repetition frequency, etc.) can be calculated based on the inherent operating parameters of the SAR payload (such as 2m strip mode, fixed 30° side-looking angle, etc.) and the observation information (position, motion state, priority, etc.) of each target to be imaged, combined with the requirements of satellite attitude control and payload imaging technology. These parameters are the core to ensure imaging quality.

[0034] After obtaining the satellite attitude parameters and SAR payload imaging parameters, the calculated parameters can be correlated with key time nodes in the imaging process: the initial attitude maneuver start time needs to allow sufficient adjustment time to ensure attitude stability before imaging; the initial imaging warm-up time is used to allow the payload to enter a stable working state; the start and end times of imaging for each target clarify the imaging period for each individual target; and the attitude recovery time is used to plan the reset process after imaging.

[0035] After the association is completed, these imaging operations with associated parameters and time nodes can be arranged in chronological order to form a unified time-series task sequence, eliminating the need for multiple replannings during the imaging process and improving imaging efficiency.

[0036] In some embodiments, the process of executing the unified time-sequential task sequence may specifically include: Before the imaging window of the first target to be imaged begins, the satellite attitude maneuver is initiated to adjust the satellite to the attitude corresponding to the fixed side-view angle. The SAR payload is powered on and warmed up at a second preset time before the imaging window of the first target to be imaged begins. The imaging operations for each target to be imaged are performed sequentially according to the task sequence, and the satellite attitude is kept unchanged during the imaging process; Between imaging operations of two adjacent targets, the SAR payload is controlled to remain in standby or be turned off based on the comparison between the interval between the imaging operations of the two adjacent targets and a third preset time threshold. After the last target to be imaged is imaged, the SAR payload is powered off and the satellite attitude is restored to its normal Earth-facing attitude.

[0037] Specifically, satellite attitude maneuvers can be initiated at a first preset time before the imaging window of the first target to be imaged, adjusting the satellite to a fixed side-looking angle based on calculated attitude parameters, allowing sufficient time to ensure attitude stability before imaging. Next, at a second preset time before the imaging window of the first target, the SAR payload is powered on for warm-up, allowing it to transition from standby to a stable operating state and ensuring initial imaging quality. Subsequently, imaging operations for each target are executed sequentially according to the generated task sequence, maintaining the satellite's attitude throughout the imaging process to avoid imaging interruptions or quality degradation due to attitude adjustments. During the imaging intervals between adjacent targets, the payload's operating state is dynamically controlled based on a comparison between the interval time and a third preset time threshold, balancing imaging efficiency and energy consumption. Finally, after the imaging of the last target is completed, the SAR payload is promptly shut down to avoid unnecessary power consumption, and an attitude recovery procedure is initiated to reset the satellite to its normal Earth-facing attitude, without affecting the execution of subsequent tasks.

[0038] In some embodiments, the process of controlling the SAR payload to remain in standby or off based on a comparison between the interval between imaging operations of two adjacent targets and a third preset time threshold may include: If the interval time is greater than the third preset time threshold, the SAR payload is controlled to shut down after the current target imaging ends, and restarted for warm-up before the second preset time before the next target imaging window begins. If the interval time is less than or equal to the third preset time threshold, the SAR payload is controlled to remain in standby mode after the current target imaging ends.

[0039] Specifically, during continuous imaging, a third preset time threshold is set as a judgment criterion for the imaging interval between two adjacent targets. When the interval is greater than this threshold, it indicates that the interval is too long. Keeping the payload in standby mode would cause unnecessary energy waste. Therefore, the payload is turned off after the current target imaging is completed, and restarted for warm-up according to the second preset time before the next target imaging to ensure that the payload is in a stable state when the next target is imaged. When the interval is less than or equal to this threshold, it indicates that the interval is too short. The warm-up time cost of restarting is higher than the standby energy consumption. Therefore, the payload is controlled to remain in standby mode to quickly connect to the next target imaging and avoid imaging delays caused by power-on / off.

[0040] In some embodiments, the imaging method of this embodiment may further include: The acquired raw SAR imaging data is compressed and classified. The contour and location identifier of each target to be imaged are extracted as high-priority data, and the complete image data is used as low-priority data. The high-priority data is transmitted back in real time via the BeiDou short message channel; The low-priority data is transmitted back to the ground station via a conventional data transmission channel when the satellite passes over.

[0041] Specifically, the raw SAR imaging data can be processed as follows: compression reduces the data volume, facilitating storage and transmission; classification processing extracts contours and location markers that quickly reflect key target information as high-priority data based on data importance and application requirements, meeting real-time needs such as emergency rescue, while complete image data is used as low-priority data for subsequent detailed analysis. Then, a differentiated backhaul strategy is adopted for data of different priorities: high-priority data is backhauled in real-time via the BeiDou short message channel, utilizing the channel's real-time transmission capability to ensure critical information is quickly delivered to the ground; low-priority data, due to its larger volume, is backhauled in batches via conventional data transmission channels when the satellite passes over the ground station, fully utilizing the communication window and reducing the occupancy of real-time channels.

[0042] In some embodiments, the process of extracting the contour and location identifier of each target to be imaged as high-priority data may include: For each target's SAR imaging results, the onboard intelligent processing unit executes ship target detection and contour extraction algorithms to identify and vectorize the ship's external contour. By combining the target's identity information provided by the onboard AIS, the outline data is associated and encapsulated with the hull number, ship type, and nationality identifier; The amount of high-priority data is controlled within the single transmission capacity of BeiDou short messages, and its transmission priority is higher than that of low-priority complete image data. The low-priority complete image data is lossily compressed before being transmitted back to reduce the load on the data transmission channel and is sent in batches when the satellite passes over the ground station.

[0043] Specifically, for high-priority data extraction, a specialized ship target detection and contour extraction algorithm is executed by the onboard intelligent processing unit to accurately identify and vectorize the ship's external contour, ensuring concise and accurate contour data. Combined with target identity information (hull number, ship type, nationality, etc.) provided by the onboard AIS, the contour data is associated and encapsulated with this identity information, giving high-priority data both morphological and positional information and identification capabilities, thus enhancing its practical value. Simultaneously, the volume of high-priority data is strictly controlled to ensure compatibility with the single transmission capacity of BeiDou short messages, preventing transmission failures, and clearly prioritizing it over low-priority data to ensure the priority delivery of critical information. For low-priority data, lossy compression is performed before transmission to further reduce the data volume while maintaining a certain image quality, alleviating the load on the data transmission channel, facilitating batch transmission during satellite overflight, and improving transmission efficiency.

[0044] This implementation ensures that critical monitoring information can be transmitted back in real time through low-bandwidth channels, while complete data is efficiently archived. It achieves coordinated optimization of on-board data processing and downlink, and improves the data service capabilities of the entire system.

[0045] Based on the same general inventive concept, this invention also protects a multi-target simultaneous temporal optimization imaging system for a spaceborne AIS-guided SAR payload. The multi-target simultaneous temporal optimization imaging system for a spaceborne AIS-guided SAR payload provided by this invention will be described below. The multi-target simultaneous temporal optimization imaging system for a spaceborne AIS-guided SAR payload described below can be referred to in correspondence with the multi-target simultaneous temporal optimization imaging method for a spaceborne AIS-guided SAR payload described above.

[0046] Figure 2 This is a schematic diagram of the structure of the multi-target simultaneous temporal optimization imaging system for a spaceborne AIS-guided SAR payload provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the spaceborne AIS-guided SAR payload multi-target same-side time-series optimized imaging system of this embodiment includes an acquisition module 21, a filtering module 22, a prediction module 23, a generation module 24, and an execution module 25.

[0047] The acquisition module 21 is used to acquire observation information of multiple candidate targets; the observation information includes pose information and priority information. The filtering module 22 is used to filter out targets located on the same side of the satellite and whose lateral distance meets the preset side-view angle constraint from the multiple candidate targets based on the satellite body coordinate system, and to select them as same-side candidate targets. The prediction module 23 is used to predict the imaging window of each target based on the observation information and satellite orbit parameters of each target in the same-side candidate targets, and to determine at least two targets to be imaged from the same-side candidate targets for continuous imaging according to the continuity of the imaging window and the preset total imaging duration constraint. The generation module 24 is used to generate a unified time-series task sequence containing imaging operations and time nodes of all targets to be imaged, based on the inherent operating parameters of the SAR payload and the observation information of each target to be imaged. The execution module 25 is used to execute the unified time-sequential task sequence, continuously image the at least two targets to be imaged at a fixed side-view angle, adaptively control the working state of the SAR payload according to the imaging interval during the continuous imaging process, and control the SAR payload to shut down and the satellite attitude to be restored after the imaging of the last target to be imaged is completed.

[0048] Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. The electronic device may include a processor 310, a communications interface 320, a memory 330, and a communication bus 340. The processor 310, communications interface 320, and memory 330 communicate with each other via the communication bus 340. The processor 310 can call logical instructions from the memory 330 to execute a multi-target simultaneous temporal optimization imaging method for a spaceborne AIS-guided SAR payload.

[0049] Furthermore, the logical instructions in the aforementioned memory 330 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0050] It should be noted that all relevant information that may be involved in the various embodiments of the present invention is processed in strict accordance with the requirements of laws and regulations, following the principles of legality, legitimacy, and necessity, based on the reasonable purpose of the business scenario, and is information that users actively provide or generate during the use of the product / service, as well as information obtained with user authorization.

[0051] The information processed by this invention may vary depending on the specific product / service scenario and should be based on the specific scenario in which the user uses the product / service. This may involve user account information, device information, or other related information. This invention will treat the relevant information and its processing with the utmost diligence.

[0052] This invention places great emphasis on the security of relevant information and has adopted reasonable and feasible security protection measures that comply with industry standards to protect user information and prevent unauthorized access, public disclosure, use, modification, damage or loss of relevant information.

[0053] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0054] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing the imaging of multiple targets by a SAR payload guided by an AIS on-board, characterized in that, The method comprises the following steps: Obtaining observation information of a plurality of candidate targets; The observation information comprises pose information and priority information; Filtering, based on a satellite body coordinate system, targets located on the same side of the satellite and having a lateral distance satisfying a preset side-view angle constraint from the plurality of candidate targets as same-side candidate targets; Based on the observation information of each target in the same-side candidate targets and satellite orbit parameters, predicting an imaging window of each target, and determining at least two to-be-imaged targets for continuous imaging from the same-side candidate targets according to the continuity of the imaging window and a preset total imaging time length constraint; According to the inherent working parameters of the SAR load and the respective observation information of each to-be-imaged target, generating a unified time-sequenced task sequence containing imaging operations and time nodes of all to-be-imaged targets; Performing the unified time-sequenced task sequence to continuously image the at least two to-be-imaged targets at a fixed side-view angle, and adaptively controlling the working state of the SAR load according to an imaging interval during the continuous imaging, and controlling the SAR load to shut down and the satellite attitude to recover after the imaging of the last to-be-imaged target is completed.

2. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 1, characterized in that, Filtering, based on a satellite body coordinate system, targets located on the same side of the satellite and having a lateral distance satisfying a preset side-view angle constraint from the plurality of candidate targets as same-side candidate targets, comprising: Establishing a satellite body coordinate system with the satellite center as the origin, the first axis along the flight direction, the second axis perpendicular to the orbit plane and outward, and the third axis pointing to the center of the Earth; Converting the position coordinates of each candidate target to the satellite body coordinate system and calculating the Y-axis coordinates and the lateral distance relative to the nadir point of each candidate target; Filtering out targets with consistent second-axis coordinate signs and a lateral distance less than or equal to a preset distance threshold as the same-side candidate targets.

3. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 2, characterized in that, The preset distance threshold is determined based on the orbit height and the fixed side-view angle.

4. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 1, characterized in that, Determining at least two to-be-imaged targets for continuous imaging from the same-side candidate targets according to the continuity of the imaging window and a preset total imaging time length constraint, comprising: According to the motion state of each same-side candidate target and the satellite orbit parameters, predicting the time when each same-side candidate target enters and exits the SAR imaging coverage range through a kinematic model to obtain the start time and the end time of the imaging window; Calculating the imaging time of each same-side candidate target; Sorting all same-side candidate targets in the order from near to far to the satellite nadir point; Judging whether the start time of the latter target in the imaging window of the adjacent targets after sorting is greater than or equal to the end time of the former target; From the targets with continuous imaging windows, calculating the sum of the imaging times of the targets with continuous imaging windows; In combination with the priority information, selecting at least two targets with a sum of imaging times not exceeding a preset total time length upper limit as to-be-imaged targets.

5. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 4, characterized in that, Further comprising: If the sum of the imaging times exceeds the preset total time length upper limit, eliminating targets in the order from high to low according to the priority or in the order from long to short according to the imaging time, until the sum of the imaging times does not exceed the preset total time length upper limit. 6.The space-borne AIS guiding SAR payload multi-target same-side timing optimization imaging method according to claim 1, characterized in that, According to the inherent working parameters of the SAR payload and the observation information of each target to be imaged, a unified time-sequenced task sequence containing the imaging operations and time nodes of all the targets to be imaged is generated, including: According to the inherent working parameters of the SAR payload and the observation information of each target to be imaged, the satellite attitude parameters and the SAR payload imaging parameters are calculated; The satellite attitude parameters and the SAR payload imaging parameters are associated with the first attitude maneuver start time, the first imaging warm-up time, the imaging start and end time of each target to be imaged, and the attitude recovery time; A time-sequenced task sequence containing the imaging operations of all the targets to be imaged is formed.

7. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 1, characterized in that, The unified time-sequenced task sequence is executed to continuously image the at least two targets to be imaged at a fixed side-looking angle, and the working state of the SAR payload is adaptively controlled according to the imaging interval during the continuous imaging, and the SAR payload is shut down and the satellite attitude is recovered after the imaging of the last target to be imaged is completed, including: At a first preset time before the imaging window of the first target to be imaged starts, a satellite attitude maneuver is started to adjust the satellite to the attitude corresponding to the fixed side-looking angle; At a second preset time before the imaging window of the first target to be imaged starts, the SAR payload is controlled to start and warm up; The imaging operations of each target to be imaged are sequentially performed according to the task sequence, and the satellite attitude remains unchanged during imaging; Between the imaging operations of adjacent two targets to be imaged, the SAR payload is controlled to remain standby or shut down according to the comparison result of the interval time of the imaging operations of the adjacent two targets to be imaged and a third preset time threshold; After the imaging of the last target to be imaged is completed, the SAR payload is shut down and the satellite attitude is recovered to the normal attitude on the ground.

8. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 7, characterized in that, The SAR payload is controlled to remain standby or shut down according to the comparison result of the interval time of the imaging operations of adjacent two targets to be imaged and a third preset time threshold, including: If the interval time is greater than the third preset time threshold, the SAR payload is controlled to shut down after the imaging of the current target ends, and to start and warm up again at the second preset time before the start of the imaging window of the next target; If the interval time is less than or equal to the third preset time threshold, the SAR payload is controlled to remain in a standby state after the imaging of the current target ends. 9.The space-borne AIS guiding SAR payload multi-target same-side timing optimization imaging method according to claim 1, characterized in that, Further including: The acquired original SAR imaging data is compressed and classified, and the outline and position identification of each target to be imaged are extracted as high-priority data, and the complete image data is extracted as low-priority data; The high-priority data is real-time returned through the Beidou short message channel; The low-priority data is returned through the conventional data transmission channel when the satellite passes through the ground station.

10. The space-borne AIS-guided SAR payload multi-target same-side timing optimization imaging method according to claim 9, characterized in that, The outline and position identification of each target to be imaged are extracted as high-priority data, including: For the SAR imaging result of each target, a ship target detection and outline extraction algorithm is executed by an on-board intelligent processing unit to identify and vectorize the ship outline; The outline data is associated and encapsulated with the hull number, ship type, and nationality identification in combination with the target identity information provided by the on-board AIS. The data amount of the high-priority data is controlled within the single transmission capacity of the Beidou short message, and the transmission priority is higher than that of the low-priority complete image data; The low-priority complete image data is lossily compressed before being returned, so as to reduce the load of the data transmission channel, and is batch-delivered when the satellite passes the ground station.

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