Autonomous imaging path and parameter planning method and system for space-borne high-resolution wide-swath SAR

Abstract

The application provides a kind of spaceborne high-resolution wide swath scanning SAR autonomous imaging path and parameter planning method and system, and can be used for spaceborne high-resolution wide swath scanning SAR multi-target on-orbit autonomous imaging path and parameter planning.The method comprises steps: (1) after receiving autonomous task imaging target by spaceborne high-resolution wide swath scanning SAR, the parameters of each target point are calculated, and the target points not in the imaging bandwidth are removed; (2) the imaging task number is planned; (3) the target selection in each imaging task is carried out; (4) the path planning and imaging time period division of each imaging task are carried out; (5) the single imaging time period imaging starting wave position calculation is carried out; (6) the SAR imaging task is executed using the calculation results of the first two steps, and the target autonomous task observation is carried out.The application can effectively improve the spaceborne high-resolution wide swath scanning SAR autonomous task planning efficiency, and improve the spaceborne high-resolution wide swath scanning SAR target general survey, monitoring application efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of spaceborne SAR imaging mission planning, specifically to a method and system for planning autonomous imaging paths and parameters for spaceborne high-resolution wide-swath SAR. Background Technology

[0002] With the development of spaceborne SAR technology, satellite imaging and monitoring tasks have become more complex. To improve the efficiency and frequency of ground target surveys and monitoring, the demand for satellite imaging planning is constantly increasing. Traditional command data is too large, the process is cumbersome, and the execution of imaging tasks is inconvenient. With the development of satellite technology, the means of SAR satellite target acquisition have gradually evolved from the past single method of manual input to sending observation target information to SAR satellites through inter-satellite links, relay satellite links, and handheld terminal devices, enabling rapid transmission of target information and rapid distribution of imaging task requirements. Since high-resolution wide-swath SAR satellites are suitable for target surveys, when facing imaging tasks involving multiple ground targets, it is necessary to plan the SAR imaging path and determine the imaging parameters. It is necessary to design the optimal imaging path and imaging parameters based on the imaging characteristics of SAR and the thermal properties of the targets to obtain maximum imaging efficiency and target coverage. Due to inconsistent ground distribution and observation priorities, the time and orbital limitations in high-resolution wide-swath SAR imaging prevent complete coverage of all targets. To address these issues, there is an urgent need to study on-orbit autonomous imaging path and parameter planning methods for high-resolution wide-swath SAR, in order to maximize the on-orbit value and effectiveness of high-resolution wide-swath SAR.

[0003] Patent document CN112330091 discloses a method for autonomous mission planning of spaceborne SAR imaging, solving the problem of on-orbit autonomous imaging mission planning for high-precision, small-swath, multi-target imaging tasks. This invention, based on the high-resolution, wide-swath scanning SAR, divides the imaging times and time periods according to imaging characteristics and requirements, and combines the overall satellite resource capabilities to more effectively achieve target imaging path and parameter planning.

[0004] Patent document CN109741837 discloses an on-board autonomous imaging mission planning system. Satellite users only need to send the latitude and longitude of the imaging area to the satellite. The satellite autonomously calculates and sets imaging and control parameters, and intelligently arranges imaging. Users do not need to understand complex satellite design and usage methods, thus enabling convenient, fast, and efficient imaging of the target area while avoiding command scheduling errors that could affect satellite safety. This invention plans SAR imaging paths and parameters by receiving target mission information from the ground or between satellites, directly guiding the SAR satellite system in imaging.

[0005] Patent document CN105068549 discloses a method for autonomous continuous planning of satellite missions. This method solves the problem of satellites accurately perceiving their own state and external environment without relying on external control and information injection, and autonomously controlling the satellite to complete various tasks. This improves the satellite's autonomous working capability and reduces the risk of fatal satellite malfunctions. This invention is suitable for remote sensing satellites that operate normally for long periods for imaging. SAR satellites, due to energy and operating time limitations, need to perform target classification imaging. This invention can appropriately allocate the number of imaging tasks and determine the imaging time periods within the imaging tasks according to the on-orbit operating constraints of SAR satellites, making it suitable for SAR on-orbit operating modes.

[0006] Patent document CN109214564 discloses an autonomous mission planning method for Earth remote sensing satellites with multiple planning modes. It performs long-term pre-coarse mission planning for the observed target and short-term local planning based on real-time updated information, making it suitable for mission planning of optical remote sensing satellites. This invention can appropriately allocate the number of imaging missions and determine the imaging time periods within each mission based on the on-orbit operating conditions of high-resolution wide-scan SAR satellites, and plan the target imaging path in real time.

[0007] ISSN 1673-8748.2020.05.002 This invention describes the onboard real-time mission planning and design for agile SAR satellites, establishing a planning-decision strategy that uses a rolling approach of long planning windows and short decision windows, and designing an onboard real-time mission planning and execution process that is triggered by events or implemented at fixed intervals. While planning imaging targets, this invention rationally designs the number of imaging missions and the division of imaging time periods within each imaging mission based on the operational status of high-resolution wide-scan SAR satellites, and plans the imaging parameters.

[0008] Based on the search of the above five patents and articles, and combined with existing technologies, there is an urgent need to research and establish an on-orbit autonomous path and imaging parameter planning method for high-resolution wide-scan SAR. After the satellite receives the observed target via ground or inter-satellite communication, it can effectively screen the target and efficiently plan the path and imaging parameters suitable for high-resolution wide-scan SAR. This will play a decisive role in improving the imaging efficiency and performance of high-resolution wide-scan SAR. The key technologies to be solved and the technical platform to be established will not only fill the domestic gap, but also support the autonomous planning of imaging paths and parameters for SAR satellites.

[0009] Therefore, a new technical solution needs to be proposed. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for autonomous imaging path and parameter planning for spaceborne high-resolution wide-swath SAR.

[0011] According to the present invention, a method for autonomous imaging path and parameter planning of spaceborne high-resolution wide-swath SAR is provided, the method comprising the following steps:

[0012] Step S1: After receiving the target imaged by the autonomous mission, the high-resolution wide-swath SAR completes the target parameter calculation and removes target points that are no longer in the imaging bandwidth.

[0013] Step S2: Plan the number of imaging tasks;

[0014] Step S3: Select the target for each imaging task;

[0015] Step S4: Perform path planning and imaging time segmentation for each imaging task;

[0016] Step S5: Calculate the initial imaging wave position within a single imaging time period;

[0017] Step S6: Use the calculation results to perform SAR target observation tasks.

[0018] Preferably, in step S1, the target information includes target confidence, target priority, target type, and target discovery time information. The overpass time, downward viewing angle, and target imaging wavefront parameters are calculated for each target point. The target points are sorted according to their overpass time, and target points that are not in the imaging bandwidth are removed.

[0019] Preferably, in step S2, the n target points are divided according to the overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. The n targets are divided into w groups in sequence, and the number of imaging tasks is planned as w.

[0020] Preferably, in step S3, target selection for each imaging task includes the following steps:

[0021] Step S3.1: Establish left and right side-view target arrays. In each task, form m left-view targets and k right-view targets according to the order of imaging time.

[0022] Step S3.2: Calculate the weight values ​​of the observed targets in the left and right side-view data;

[0023] Weight values ​​of the observed targets in the left-side view data:

[0024]

[0025] Weight values ​​of the observed targets in the right-side view data:

[0026]

[0027] Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively, and Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground, and the on-orbit dynamic annotation number is modified.

[0028] Step S3.3: Compare the weights of left and right side views and determine the observation targets. If G_left ≥ G_right, retain m targets; otherwise, retain k targets.

[0029] Preferably, in step S4, the imaging path planning and single imaging time calculation based on the selected target includes the following steps:

[0030] Step S4.1: Taking the imaging time T of the first point as the starting point, advance ΔT as the start time of this imaging mission. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time.

[0031] Step S4.2: Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, divide the first imaging period into (T-ΔT, Tγ+T3-ΔT) and determine the number of imaging targets in the first period.

[0032] Step S4.3: Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is re-divided. A single imaging task can be divided into s imaging time periods.

[0033] Preferably, step S5, which involves calculating the initial imaging wavelength within a single imaging time period, includes the following steps:

[0034] Step S5.1: Within each imaging time period, determine the number of targets, and then determine the number of scanning sub-bands and the wavenumber imaging parameters according to the imaging mode;

[0035] Step S5.2: Calculate the weight of all targets in each imaging sub-band in a loop, and select the starting wave position with the largest target weight in the loop as the starting wave position for that imaging.

[0036] This invention also provides a spaceborne high-resolution wide-swath SAR autonomous imaging path and parameter planning system, the system comprising the following modules:

[0037] Module M1: After receiving the image target of the autonomous mission, the high-resolution wide-swath SAR completes the target parameter calculation and removes target points that are no longer in the imaging bandwidth;

[0038] Module M2: Plans the number of imaging tasks;

[0039] Module M3: Selects targets for each imaging mission;

[0040] Module M4: Performs path planning and imaging time segmentation for each imaging task;

[0041] Module M5: Calculates the initial imaging wave position within a single imaging time period;

[0042] Module M6: Uses the calculation results to perform SAR target observation tasks.

[0043] Preferably, in module M1, the target information includes target confidence, target priority, target type, and target discovery time information. For each target point, the overpass time, downward viewing angle, and target imaging wavelet parameters are calculated. The target points are sorted according to their overpass time, and target points that are not in the imaging bandwidth are removed.

[0044] Preferably, in module M2, the n target points are divided according to the overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. The n targets are divided into w groups in sequence, and the number of imaging tasks is planned as w.

[0045] Module M3, which performs target selection for each imaging task, includes the following modules:

[0046] Module M3.1: Establishes left and right side-view target arrays, forming m left-view targets and k right-view targets in each mission according to the order of imaging time;

[0047] Module M3.2: Calculates the weight values ​​of the observed targets in the left and right side-view data;

[0048] Weight values ​​of the observed targets in the left-side view data:

[0049]

[0050] Weight values ​​of the observed targets in the right-side view data:

[0051]

[0052] Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively, and Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground, and the on-orbit dynamic annotation number is modified.

[0053] Module M3.3: Compare the weights of left and right side looks and determine the observed targets. If G_left ≥ G_right, retain m targets; otherwise, retain k targets.

[0054] Preferably, module M4, which plans the imaging path and calculates the single imaging time based on the selected target, includes the following modules:

[0055] Module M4.1: Starting from the imaging time T of the first point, the start time of this imaging mission is ΔT in advance. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time.

[0056] Module M4.2: Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, the first imaging period is divided into (T-ΔT, Tγ+T3-ΔT) to determine the number of imaging targets in the first period.

[0057] Module M4.3: Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is re-divided. A single imaging task can be divided into s imaging time periods.

[0058] Module M5 performs the calculation of the initial imaging wavelength within a single imaging time period, including the following modules:

[0059] Module M5.1: Within each imaging time period, determine the number of targets, and then determine the number of scanning sub-bands and wavenumber imaging parameters according to the imaging mode;

[0060] Module M5.2: Iteratively calculates the weight of all targets in each imaging sub-band, selects the starting wave position with the largest target weight in the loop, and uses it as the starting wave position for that imaging.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] This invention provides an autonomous mission planning method for spaceborne SAR imaging, which solves the problem of on-orbit autonomous imaging mission planning for spaceborne high-resolution wide-swath scanning SAR under multi-target imaging missions. Based on the characteristics of ground targets, the method autonomously determines the number of imaging missions and the division of imaging time periods for the observed targets, and autonomously determines reasonable imaging paths and imaging parameters to achieve high-efficiency imaging observation of multiple target points by SAR. Attached Figure Description

[0063] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0064] Figure 1 This is a flowchart of the high-resolution wide-swath SAR autonomous imaging path and parameter planning method of the present invention. Detailed Implementation

[0065] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0066] Example 1:

[0067] According to the present invention, a method for autonomous imaging path and parameter planning of spaceborne high-resolution wide-swath SAR is provided, the method comprising the following steps:

[0068] Step S1: After receiving the autonomous mission imaging target, the high-resolution wide-swath SAR completes the target parameter calculation and removes target points that are no longer in the imaging bandwidth. Target information includes target confidence, target priority, target type, and target discovery time. For each target point, the overpass time, downward viewing angle, and target imaging wavefront parameters are calculated. The target points are sorted according to their overpass time and target points that are no longer in the imaging bandwidth are removed.

[0069] Step S2: Plan the number of imaging tasks; Divide the n target points according to their overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. Divide the n targets into w groups in sequence, and plan the number of imaging tasks as w.

[0070] Step S3: Target selection for each imaging mission; target selection for each imaging mission includes the following steps:

[0071] Step S3.1: Establish left and right side-view target arrays. In each task, form m left-view targets and k right-view targets according to the order of imaging time.

[0072] Step S3.2: Calculate the weight values ​​of the observed targets in the left and right side-view data;

[0073] Weight values ​​of the observed targets in the left-side view data:

[0074]

[0075] Weight values ​​of the observed targets in the right-side view data:

[0076]

[0077] Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively, and Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground, and the on-orbit dynamic annotation number is modified.

[0078] Step S3.3: Compare the weights of left and right side views and determine the observation targets. If G_left ≥ G_right, retain m targets; otherwise, retain k targets.

[0079] Step S4: Perform path planning and imaging time segmentation for each imaging task; plan the imaging path and calculate the single imaging time based on the selected target, including the following steps:

[0080] Step S4.1: Taking the imaging time T of the first point as the starting point, advance ΔT as the start time of this imaging mission. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time.

[0081] Step S4.2: Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, divide the first imaging period into (T-ΔT, Tγ+T3-ΔT) and determine the number of imaging targets in the first period.

[0082] Step S4.3: Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is re-divided. A single imaging task can be divided into s imaging time periods.

[0083] Step S5: Calculate the initial imaging wavelength within a single imaging time period; Calculating the initial imaging wavelength within a single imaging time period includes the following steps:

[0084] Step S5.1: Within each imaging time period, determine the number of targets, and then determine the number of scanning sub-bands and the wavenumber imaging parameters according to the imaging mode;

[0085] Step S5.2: Calculate the weight of all targets in each imaging sub-band in a loop, and select the starting wave position with the largest target weight in the loop as the starting wave position for that imaging.

[0086] Step S6: Use the calculation results to perform SAR target observation tasks.

[0087] The present invention also provides a spaceborne high-resolution wide-swath scanning SAR autonomous imaging path and parameter planning system. The spaceborne high-resolution wide-swath scanning SAR autonomous imaging path and parameter planning system can be implemented by executing the process steps of the spaceborne high-resolution wide-swath scanning SAR autonomous imaging path and parameter planning method. That is, those skilled in the art can understand the spaceborne high-resolution wide-swath scanning SAR autonomous imaging path and parameter planning method as a preferred embodiment of the spaceborne high-resolution wide-swath scanning SAR autonomous imaging path and parameter planning system.

[0088] Example 2:

[0089] This invention also provides a spaceborne high-resolution wide-swath SAR autonomous imaging path and parameter planning system, the system comprising the following modules:

[0090] Module M1: After receiving the target imaged by the autonomous mission, the high-resolution wide-swath SAR completes the target parameter calculation and removes target points that are no longer in the imaging bandwidth. The target information includes target confidence, target priority, target type, and target discovery time information. For each target point, the overhead time, downward viewing angle, and target imaging wavefront parameters are calculated. The target points are sorted according to their overhead time and target points that are not in the imaging bandwidth are removed.

[0091] Module M2: Plans the number of imaging tasks; divides n target points according to their overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or if the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. The n targets are divided into w groups in sequence, and the number of imaging tasks is planned to be w.

[0092] Module M3: Performs target selection for each imaging mission; Target selection for each imaging mission includes the following modules:

[0093] Module M3.1: Establishes left and right side-view target arrays, forming m left-view targets and k right-view targets in each mission according to the order of imaging time;

[0094] Module M3.2: Calculates the weight values ​​of the observed targets in the left and right side-view data;

[0095] Weight values ​​of the observed targets in the left-side view data:

[0096]

[0097] Weight values ​​of the observed targets in the right-side view data:

[0098]

[0099] Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively, and Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground, and the on-orbit dynamic annotation number is modified.

[0100] Module M3.3: Compare the weights of left and right side looks and determine the observed targets. If G_left ≥ G_right, retain m targets; otherwise, retain k targets.

[0101] Module M4: Performs path planning and imaging time segmentation for each imaging task; it plans the imaging path and calculates the single imaging time based on the selected target, including the following modules:

[0102] Module M4.1: Starting from the imaging time T of the first point, the start time of this imaging mission is ΔT in advance. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time.

[0103] Module M4.2: Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, the first imaging period is divided into (T-ΔT, Tγ+T3-ΔT) to determine the number of imaging targets in the first period.

[0104] Module M4.3: Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is re-divided. A single imaging task can be divided into s imaging time periods.

[0105] Module M5: Calculates the initial imaging wavelength within a single imaging time period; This includes the following modules:

[0106] Module M5.1: Within each imaging time period, determine the number of targets, and then determine the number of scanning sub-bands and wavenumber imaging parameters according to the imaging mode;

[0107] Module M5.2: Iteratively calculates the weight of all targets in each imaging sub-band, selects the starting wave position with the largest target weight in the loop, and uses it as the starting wave position for that imaging.

[0108] Module M6: Uses the calculation results to perform SAR target observation tasks.

[0109] Example 3:

[0110] To address the problem of autonomous imaging path and parameter planning for high-resolution wide-swath SAR, and to improve the efficiency of mission imaging and the ease of mission injection, this invention provides a method for autonomous imaging path and parameter planning for high-resolution wide-swath SAR.

[0111] In this embodiment, the high-resolution wide-swath scanning SAR satellite is operating normally and stably in orbit, and target injection can be performed through ground-based uploading or inter-satellite links.

[0112] like Figure 1 As shown, in step one: after the high-resolution wide-swath SAR receives the target image of the autonomous mission, the target information includes the target confidence, target priority, target type, target discovery time, etc. For each target point, the parameters such as the overpass time, downward viewing angle, and target imaging wave position are calculated. The target points are sorted according to their overpass time, and target points that are not in the imaging bandwidth are removed.

[0113] Step 2: Plan the number of imaging tasks; Divide the n target points according to their overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. Divide the n targets into w groups in sequence, and plan the number of imaging tasks as w.

[0114] Step 3: Select targets for each imaging mission;

[0115] (a) Establish left and right side-view target arrays (w is the number of missions). In each mission, form m left-view targets and k right-view targets according to the order of imaging time.

[0116] (b) Calculate the weight values ​​of the targets observed in the left and right side-view data.

[0117] Weight values ​​of the observed targets in the left-side view data:

[0118]

[0119] Weight values ​​of the observed targets in the right-side view data:

[0120]

[0121] Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively. Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground. The on-orbit dynamic annotation number can be modified to facilitate users to modify the characteristics of the imaging target.

[0122] (c) Compare the weights of left and right side views and determine the observation targets: if G_left ≥ G_right, retain m targets; otherwise, retain k targets.

[0123] Step 4: Perform path planning and imaging time segmentation for each imaging task;

[0124] (a) Taking the imaging time T of the first point as the starting point, ΔT is taken as the start time of this imaging mission. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time.

[0125] (b) Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, the first imaging period is divided into (T-ΔT, Tγ+T3-ΔT) to determine the number of imaging targets in the first period.

[0126] (c) Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is divided again. A single imaging task can be divided into s imaging time periods.

[0127] Step 5: Calculate the initial imaging wave position within a single imaging time period;

[0128] (a) Within each imaging time period, the number of targets is determined, and then imaging parameters such as the number of scanning sub-bands and the number of wavenumbers are determined according to the imaging mode;

[0129] (b) Calculate the weight of all targets in each imaging sub-band in a loop, and select the starting position of the target with the largest weight in the loop as the starting position of the imaging.

[0130] Step 6: Use the calculation results from the first two steps to perform the SAR target observation task.

[0131] In summary, this invention fills a gap in the prior art, solves the problem of on-orbit autonomous imaging mission planning for spaceborne high-resolution wide-swath scanning SAR under multi-target imaging tasks, and autonomously determines the number of imaging missions and the division of imaging time periods for the observed targets based on the characteristics of the ground targets, and autonomously determines reasonable imaging paths and imaging parameters, so as to realize high-efficiency imaging observation of multiple target points by SAR.

[0132] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1 and Embodiment 2.

[0133] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0134] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for autonomous imaging path and parameter planning of spaceborne high-resolution wide-swath SAR, characterized in that, The method includes the following steps: Step S1: After receiving the autonomous mission imaging target, the high-resolution wide-swath SAR completes the target parameter calculation and removes target points that are not in the imaging bandwidth. Step S2: Plan the number of imaging tasks; Step S3: Select the target for each imaging task; Step S4: Perform path planning and imaging time segmentation for each imaging task; Step S5: Calculate the initial imaging wave position within a single imaging time period; Step S6: Use the calculation results to perform SAR target observation tasks; In step S2, the n target points are divided according to the overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. The n targets are divided into w groups in sequence, and the number of imaging tasks is planned as w. In step S3, target selection for each imaging task includes the following steps: Step S3.1: Establish left and right side-view target arrays. In each task, form m left-view targets and k right-view targets according to the order of imaging time. Step S3.2: Calculate the weight values ​​of the observed targets in the left and right side-view data; Weight values ​​of the observed targets in the left-side view data: Weight values ​​of the observed targets in the right-side view data: Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively, and Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground, and the on-orbit dynamic annotation number is modified. Step S3.3: Compare the weights of left and right side views and determine the observed targets. If G_left ≥ G_right, retain m targets; otherwise, retain k targets. In step S4, imaging path planning is performed based on the selected target, and the single imaging time is calculated, including the following steps: Step S4.1: Taking the imaging time T of the first point as the starting point, advance ΔT as the start time of this imaging mission. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time. Step S4.2: Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, the first imaging period is divided into (T-ΔT, Tγ+T3-ΔT) to determine the number of imaging targets in the first period. Step S4.3: Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is re-divided. A single imaging task can be divided into s imaging time periods.

2. The method for autonomous imaging path and parameter planning of spaceborne high-resolution wide-swath SAR according to claim 1, characterized in that, In step S1, the target information includes target confidence, target priority, target type, and target discovery time information. For each target point, the overpass time, downward viewing angle, and target imaging wavefront parameters are calculated. The target points are sorted according to their overpass time, and target points that are not in the imaging bandwidth are removed.

3. The method for autonomous imaging path and parameter planning of spaceborne high-resolution wide-swath SAR according to claim 1, characterized in that, In step S5, the initial imaging wavelength is calculated within a single imaging time period, including the following steps: Step S5.1: Within each imaging time period, determine the number of targets, and then determine the number of scanning sub-bands and the wavenumber imaging parameters according to the imaging mode; Step S5.2: Calculate the weight of all targets in each imaging sub-band in a loop, and select the starting wave position with the largest target weight in the loop as the starting wave position for that imaging.

4. A spaceborne high-resolution wide-swath SAR autonomous imaging path and parameter planning system, characterized in that, The system includes the following modules: Module M1: After receiving the image target of the autonomous mission, the high-resolution wide-swath SAR completes the target parameter calculation and removes target points that are not in the imaging bandwidth; Module M2: Plans the number of imaging tasks; Module M3: Selects targets for each imaging mission; Module M4: Performs path planning and imaging time segmentation for each imaging task; Module M5: Calculates the initial imaging wave position within a single imaging time period; Module M6: Performs SAR target observation tasks using the calculation results; In module M2, n target points are divided according to their overpass time. If the overpass time of an adjacent target point is greater than the interval T1 between two SAR imaging tasks, or if the overpass time between the first point and the current point is greater than the longest time T2 in continuous SAR imaging, then the previous target point is the last point of the previous task, and the current target point is the first point of the next task. The n targets are divided into w groups in sequence, and the number of imaging tasks is planned as w. Module M3, which performs target selection for each imaging task, includes the following modules: Module M3.1: Establishes left and right side-view target arrays, forming m left-view targets and k right-view targets in each mission according to the order of imaging time; Module M3.2: Calculates the weight values ​​of the observed targets in the left and right side-view data; Weight values ​​of the observed targets in the left-side view data: Weight values ​​of the observed targets in the right-side view data: Where X[w][i][1], X[w][i][2], and X[w][i][3] are the input target characteristics, namely target confidence, target priority, and target imaging wave position, respectively, and Y[1], Y[2], and Y[3] are the weight values ​​of the characteristic parameters configured on the ground, and the on-orbit dynamic annotation number is modified. Module M3.3: Compare the weights of left and right side looks and determine the observed targets. If G_left ≥ G_right, retain m targets; otherwise, retain k targets. In module M4, imaging path planning is performed based on the selected target, and the single imaging time is calculated. This includes the following modules: Module M4.1: Starting from the imaging time T of the first point, the start time of this imaging mission is ΔT in advance. ΔT is the SAR imaging preparation time, which includes calibration time, orbital error time, and half of the aperture formation time. Module M4.2: Query the overpass time of subsequent target points until the imaging time of subsequent target point γ is greater than or equal to the single imaging time T0 and the imaging time of target point (γ+1) T(γ+1) minus the target point Tγ is greater than or equal to T3. Then, the first imaging period is divided into (T-ΔT, Tγ+T3-ΔT) to determine the number of imaging targets in the first period. Module M4.3: Starting from the imaging time T(γ+1) of the target point (γ+1), the next time period is re-divided. A single imaging task can be divided into s imaging time periods.

5. The spaceborne high-resolution wide-swath SAR autonomous imaging path and parameter planning system according to claim 4, characterized in that, In module M1, the target information includes target confidence, target priority, target type, and target discovery time information. For each target point, the overpass time, downward viewing angle, and target imaging waveform parameters are calculated. The target points are sorted according to their overpass time, and target points that are not in the imaging bandwidth are removed.

6. The spaceborne high-resolution wide-swath SAR autonomous imaging path and parameter planning system according to claim 4, characterized in that, Module M5 performs the calculation of the initial imaging wavelength within a single imaging time period, including the following modules: Module M5.1: Within each imaging time period, determine the number of targets, and then determine the number of scanning sub-bands and wavenumber imaging parameters according to the imaging mode; Module M5.2: Iteratively calculates the weight of all targets in each imaging sub-band, selects the starting wave position with the largest target weight in the loop, and uses it as the starting wave position for that imaging.

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