Space-based dynamic on-orbit scanning global isometric sector strict splicing device and method

Abstract

The present application relates to a kind of global equal-angle sector strict splicing device and method of dynamic vertical rail scanning in space-based, relate to space optical remote sensing technical field, solve the technical problem of low resource utilization efficiency in high latitude area caused by fixed swing scanning angle in prior art.The device comprises: motion simulation unit, programmable ellipsoidal surface encoding metrological reference target, space-time synchronous trigger type image acquisition unit, coverage performance evaluation and optimization unit.The present application utilizes the dynamic coupling process of scaled parallel system to reproduce satellite flight and camera swing, simulates the rotation of the earth by ellipsoidal digital array dynamic display screen, uses high-precision grid encoding target as the absolute space reference of coverage measurement, combines adaptive swing control and parameter automatic optimization, captures target image in real time and completes single-frame positioning, strip reconstruction and quantitative statistics of coverage index, and then outputs optimal scanning parameter scheme through multiple physical simulation iterations.

Description

Technical Field

[0001] This invention relates to the field of space optical remote sensing technology, and in particular to a space-based dynamic vertical rail scanning full-domain equal-angle sector-shaped tight stitching device and method. Background Technology

[0002] Space-based satellites, strictly adhering to the law of universal gravitation, orbit the Earth as a point mass in a periodic elliptical or circular orbit. In conventional global coverage mission planning, analysts often divide the satellite's scanning area based on a fixed latitude and longitude grid. However, this static constraint based on latitude and longitude lines cannot adapt to mission requirements with different orbital inclinations and flight directions, resulting in a lack of universality in scanning strategies and a tendency to produce coverage overlaps or gaps. In traditional imaging strategies, regardless of the satellite's orbit, the camera's side-swivel angle is often set to a fixed maximum value to ensure seamless coverage in the equatorial region. However, due to the Earth's curvature, the ground coverage width corresponding to the same side-swivel angle varies significantly at different latitudes: the width is greatest at the equator, decreasing according to a cosine law as latitude increases, leading to severe stripe overlap in high-latitude regions. This "one-size-fits-all" fixed scanning method creates a large amount of redundant coverage, wasting satellite imaging resources, increasing the burden of data storage and downlink, and reducing mission efficiency.

[0003] In current engineering practice, the design of scanning angles mainly relies on digital simulation. However, simulations struggle to accurately reproduce the dynamic response of the camera servo mechanism, the time-varying coupling of Earth's rotation, and the coverage area during actual imaging, leading to discrepancies between simulation results and on-orbit performance. Domestic and international research largely focuses on the design of the scanning mechanism itself or the geometric correction of images, lacking a high-fidelity, end-to-end optimal simulation system in a ground physical environment before launch to perform quantitative measurement and strategy optimization of the "satellite motion-camera scanning-surface coverage" dynamic process. This makes the design of scanning imaging missions often high-risk, hindering the provision of reliable experimental evidence for mission parameter customization and scanning strategy optimization. Summary of the Invention

[0004] This invention aims to solve the technical problems of high-latitude overlap and waste and low resource utilization efficiency caused by fixed sweep angle in the prior art, and to make the invention applicable to any trajectory, providing experimental basis for the customization of satellite camera mission parameters, and providing a space-based dynamic vertical orbit scanning full-domain equal angle sector tight stitching device and method.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A space-based dynamic vertical orbit scanning full-domain isoangular sector-shaped tight stitching device includes: a motion simulation unit, a programmable ellipsoidal coded metrological reference target, a spatiotemporally synchronized triggered image acquisition unit, and a coverage performance evaluation and optimization unit.

[0007] The motion simulation unit includes: an orbital motion module, a scanning motion module, and an orbital tilt adjustment structure; a spatiotemporally synchronized triggered image acquisition unit is set on the scanning motion module; the scanning motion module is set on the orbital motion module; the orbital tilt adjustment structure is connected to the orbital motion module and is used to adjust the tilt angle of the orbital motion module; the orbital motion module is set on the periphery of the programmable ellipsoidal coded metrological reference target;

[0008] Programmable ellipsoidal coded metrological reference targets are used to simulate the longitude drift of sub-satellite points caused by the Earth's rotation;

[0009] The scanning motion module is used to drive the spatiotemporally synchronized triggered image acquisition unit to reciprocate and swing, simulating the working mode of the on-board camera's sweeping motion. The spatiotemporally synchronized triggered image acquisition unit works in coordination with the orbital motion module and the scanning motion module to acquire local images of the programmable ellipsoidal coded metrological reference target in real time, and transmits the target image with position coding information to the coverage performance evaluation and optimization unit in real time.

[0010] The coverage performance evaluation and optimization unit is used to receive target images and real-time trajectory data from the motion simulation unit, and to calculate the grid coordinate region corresponding to each frame of image through image recognition algorithms, thereby reconstructing the continuous sweep trajectory of the instantaneous field of view on the sphere.

[0011] In the above technical solution, the spatiotemporal synchronous triggered image acquisition unit is a global shutter CMOS camera.

[0012] In the above technical solution, the track motion module includes: an arc-shaped guide rail and a guide rail slider; the arc-shaped guide rail is in the shape of a ring; the guide rail slider is set on the arc-shaped guide rail; the guide rail slider moves at a constant speed along the arc-shaped guide rail.

[0013] In the above technical solution, the scanning motion module is driven by a voice coil motor, the swing shaft is perpendicular to the plane of the arc-shaped guide rail, the maximum swing angle is ±30°, and the swing angle control accuracy is better than 0.01°.

[0014] In the above technical solution, the track motion module and the scanning motion module are uniformly scheduled by the collaborative controller and can be independently adjusted or operated in conjunction with each other according to the set speed, swing amplitude, and frequency.

[0015] In the above technical solution, the coverage performance evaluation and optimization unit is also used to, when a certain number of passes have completed full coverage of a designated area or the overlap rate is not lower than a certain threshold, traverse the combination of scanning amplitude, oscillation frequency, and orbital speed parameters, run the simulation multiple times and record the corresponding coverage performance indicators, and finally output the optimal scanning parameter scheme that meets the task constraints.

[0016] In the above technical solution, the target surface of the programmable ellipsoidal coded metrological reference target displays a grid and position coded markers. The grid rolls westward at the Earth's rotational angular velocity. Each grid cell has unique position coordinates, and the coded markers at the junction of adjacent grids are automatically identified and located by a spatiotemporally synchronized triggered image acquisition unit.

[0017] A method for full-area equiangular sector-shaped rigorous stitching of space-based dynamic vertical orbit scanning, applicable to the aforementioned full-area equiangular sector-shaped rigorous stitching device for space-based dynamic vertical orbit scanning, includes the following steps:

[0018] Step 1: Theoretical model establishment and initial parameter calculation;

[0019] Take a point on the Earth's axis of the programmable ellipsoidal coded metrological reference target, and draw a line from that point to the Earth's surface. The spherical region covered by the line is called an equiangular sector. The vertex of the equiangular sector is located on the Earth's axis, the angle between its two boundary lines is constant, and the plane containing the equiangular sector is parallel to the equatorial plane.

[0020] Define the following parameters:

[0021] This is the scaled-down radius of the Earth; This is the scaled-down orbital height; Let be the arc length of the equiangular sector corresponding to the geocentric point, which is determined by the camera's field of view. Maximum lateral sway angle and scaled-down orbital height The decision is:

[0022]

[0023] Then the geocentric angle corresponding to the equiangular sector at the Earth's center for:

[0024]

[0025] At any latitude At that point, the arc length of the line where the equiangular sector intersects the Earth's surface. satisfy:

[0026]

[0027] When the satellite flies to a position with an angular distance of δ from the equator, the coverage width for: ;in, This is the angular distance value. ∈[−π / 2,π / 2];

[0028] Step 2: Grid image acquisition and strip edge processing;

[0029] The drive time-space synchronous triggering image acquisition unit travels the entire path along the track motion module. The screen image remains still, continuously acquiring images of coded marker points. According to the trajectory defined in step 1, the device renders the meridian and sagittal line on the sphere in real time, and displays coded marker points at equal intervals in the sagittal direction to form a dynamic coordinate system and establish a mapping table.

[0030] Step 3: Calculate coverage and overlap rates;

[0031] Each grid cell on the target surface of a programmable ellipsoidal coded metrological reference target The corresponding angle range is , Area of ​​each grid cell for:

[0032]

[0033] in, and These represent the row and column indices of the grid cell, respectively. For the first The corresponding camera field of view, For the first The corresponding camera field of view, For the first The angular distance value corresponding to the row. For the first The angular distance value corresponding to the row;

[0034] The sum of the areas of all grid cells equals the total area of ​​the sphere. ;

[0035] After the transit ends, the actual grid cells covered are counted and combined. Its area for:

[0036]

[0037] Define the coverage of this transit. for:

[0038]

[0039] For a stripe with a given angular distance interval, define the overlap rate. The number of grid cells within this strip that are covered ≥ 2 times. The total number of covered grid cells within the strip The ratio:

[0040]

[0041] The curves showing the device output coverage as a function of angular distance, and the curves showing the overlap rate as a function of angular distance;

[0042] Step 4: Parameter optimization;

[0043] Set optimization goals, give acceptable coverage and overlap ranges, and automatically traverse the preset search range of relevant parameters under these constraints;

[0044] The device automatically generates a list of parameter combinations and executes steps 2 and 3 sequentially according to the list of parameter combinations, recording the cumulative coverage and overlap rate for each set of parameters. After the traversal is completed, all parameter combinations that meet the coverage target are selected and sorted according to the priority of the highest cumulative coverage rate, the fewest number of passes, and the overlap rate closest to the target median. The device then outputs the optimal scanning parameter scheme, the optimal sweep angle curve, and the corresponding coverage performance report.

[0045] The present invention has the following beneficial effects:

[0046] The space-based dynamic vertical orbit scanning full-domain equiangular sector-shaped rigorous stitching device and method of the present invention utilizes a scaled-down parallel system to reproduce the dynamic coupling process of satellite flight and camera oscillation. It simulates the Earth's rotation through an ellipsoidal digital array dynamic display screen, uses a high-precision grid-coded target as the absolute spatial reference for coverage measurement, and combines adaptive oscillation control and automatic parameter optimization to capture target images in real time and complete single-frame positioning, strip reconstruction, and quantitative statistics of coverage indicators. Then, through multiple physical simulation iterations, it outputs the optimal scanning parameter scheme, realizing the leap from digital simulation to physical calibration, from qualitative judgment to quantitative measurement, and from scheme verification to strategy optimization in scanning imaging coverage performance. It provides traceable and reproducible engineering experimental basis for mission planning and on-orbit parameter customization of scanning satellites. Attached Figure Description

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0048] Figure 1 This is a schematic diagram of the overall structure of the space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device of the present invention.

[0049] Figure 2 This is a schematic diagram of the function of the track device in the apparatus of the present invention.

[0050] Figure 3This diagram illustrates the geometric relationship of the coverage area divided into equal-angle sectors based on the Earth's axis under different orbital inclination angles. In this diagram, a) shows a flight path along a meridian, and b) shows a flight path along an arbitrary inclination angle.

[0051] Figure 4 This is a schematic diagram showing the superimposed effect of the actual scanning range after continuous passage.

[0052] Figure 5 This is a flowchart illustrating the full-domain equiangular sector-based rigorous stitching method for space-based dynamic vertical orbit scanning according to the present invention.

[0053] The reference numerals in the figure are:

[0054] 1-Horizontal base; 2-Programmable ellipsoidal coded metrological reference target; 3-Spatiotemporal synchronous triggered image acquisition unit; 4-Scanning motion module; 5-Orbit motion module; 6-Orbit tilt adjustment structure. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0056] like Figure 1 As shown, the space-based dynamic vertical orbit scanning full-domain equiangular sector-shaped tight stitching device of the present invention includes: a motion simulation unit, a programmable ellipsoidal coded metrological reference target 2, a spatiotemporal synchronous triggered image acquisition unit 3, and a coverage performance evaluation and optimization unit.

[0057] in:

[0058] The motion simulation unit is a track-scan dual-degree-of-freedom dynamic coupling motion simulation system, specifically including: track motion module 5, scanning motion module 4, and track tilt adjustment structure 6; the spatiotemporal synchronous triggered image acquisition unit 3 is set on the scanning motion module 4; the scanning motion module 4 is set on the track motion module 5; the track tilt adjustment structure 6 is connected to the track motion module 5 and is used to adjust the tilt angle of the track motion module 5.

[0059] Specifically, the spatiotemporal synchronous triggered image acquisition unit 3 is a global shutter CMOS camera, fixed at the front end of the scanning motion module 4, and operates in coordination with the track motion module 5 and the scanning motion module 4. It is used to acquire local images of the programmable ellipsoidal coded metrological reference target 2 in real time, and transmit the target image with position coding information to the coverage performance evaluation and optimization unit in real time. The global shutter CMOS camera has a resolution of 2048×2048, a lens focal length of 25mm, and a field of view of 30°.

[0060] The orbital motion module 5 includes an arc-shaped guide rail and a guide rail slider. The arc-shaped guide rail is circular. The guide rail slider is mounted on the arc-shaped guide rail and is driven by a servo motor, moving at a constant speed along the arc-shaped guide rail. The arc-shaped guide rail is positioned around the programmable ellipsoidal coded metrological reference target 2, used to enable the spatiotemporal synchronous triggering image acquisition unit 3 to move along the preset trajectory of the orbital motion module 5 along with the scanning motion module 4, simulating the orbital flight of the satellite platform. The radius of the arc-shaped guide rail is 7.016 m (corresponding to the actual on-orbit altitude of the satellite, 645 km). The guide rail slider is driven by a servo motor and can move at a constant speed along the arc-shaped guide rail. The motion speed V is determined by scaling down the actual satellite motion speed by a factor of 1 million. S =7.6 mm / s.

[0061] The scanning motion module 4 drives the spatiotemporally synchronized trigger-type image acquisition unit 3 to reciprocate, simulating the scanning operation mode of an onboard camera. The scanning motion module 4 is the camera scanning drive device, installed between the guide rail slider and the spatiotemporally synchronized trigger-type image acquisition unit 3. The scanning motion module 4 is driven by a voice coil motor, with the swing axis perpendicular to the arc-shaped guide rail plane, a maximum swing angle of ±30°, and a swing angle control accuracy better than 0.01°.

[0062] The track motion module 5 and the scanning motion module 4 are uniformly scheduled by the collaborative controller and can be independently adjusted or operated in conjunction with each other according to the set speed, swing amplitude and frequency. The collaborative controller connects all drive components and cameras to the industrial control computer to achieve synchronization of motion, screen scrolling and image acquisition.

[0063] like Figure 2 As shown, it demonstrates that the large circular arc track can be adjusted to any tilt angle to simulate any satellite orbit. Specifically, the lower end of the track tilt adjustment structure 6 is fixed on the horizontal base 1, and the upper end is connected to the left and right ends of the arc-shaped guide rail of the track motion module 5, which can drive the circular arc-shaped guide rail of the track motion module 5 to rotate around the programmable ellipsoidal coded measurement reference target 2. The arc-shaped guide rail is controlled by the track tilt adjustment structure 6 and can be adjusted to any tilt angle according to the required simulated satellite orbit. The horizontal base 1 is a precision vibration isolation platform to ensure the system reference level.

[0064] The programmable ellipsoidal coded metrological reference target 2 uses an ellipsoidal digital array dynamic display screen, which is located at the center of the circular arc-shaped guide rail of the orbital motion module 5, and is dynamically displayed by the ellipsoidal digital array dynamic display screen; its radius of curvature is also the scaled-down Earth radius. =6.371 m (at a 1:1,000,000 scale, corresponding to an Earth radius of 6371 km); the target surface of the programmable ellipsoidal coded metrological reference target 2 can display a high-precision grid and position-coded markers, with the grid based on the Earth's rotation angular velocity. Rolling westward, it simulates the longitude drift of the sub-satellite point caused by the Earth's rotation; each grid cell has unique position coordinates, and the coded marker points at the junction of adjacent grids can be automatically identified and located by the spatiotemporally synchronized triggered image acquisition unit 3; the ellipsoidal digital array dynamic display screen replaces the mechanical drive, which can eliminate the loss of rotational accuracy and mechanical wear.

[0065] The coverage performance evaluation and optimization unit receives target images and real-time trajectory data from the motion simulation unit. It uses image recognition algorithms to calculate the grid coordinates of each frame, thereby reconstructing the continuous sweep trajectory of the instantaneous field of view across the sphere during the scan. Based on this, it automatically calculates the actual coverage width, overlap rate, and total coverage. Simultaneously, this unit has a strategy iteration optimization function. Coverage targets are manually set, such as achieving full coverage of a specified area or an overlap rate not lower than a certain threshold within a maximum of a few passes (the spatiotemporally triggered image acquisition unit 3 is fixed on the guide rail slider, making periodic movements along the track and scanning a designated area; one complete revolution of the spatiotemporally triggered image acquisition unit 3 along the circular arc-shaped guide rail of the track motion module 5 constitutes one revolution, simulating the orbital motion of a satellite orbiting the Earth, while simultaneously achieving one pass over the scanned area). The system automatically iterates through combinations of parameters such as scan amplitude, oscillation frequency, and orbital speed, runs the simulation multiple times, records the corresponding coverage performance indicators, and finally outputs the optimal scanning parameter scheme that meets the task constraints.

[0066] See Figure 5 The present invention provides a method for full-area equiangular sector-shaped rigorous stitching of space-based dynamic vertical orbit scanning, applicable to the aforementioned full-area equiangular sector-shaped rigorous stitching device for space-based dynamic vertical orbit scanning, comprising the following steps:

[0067] Step 1: Theoretical model establishment and initial parameter calculation;

[0068] As the theoretical basis of this invention, an isoangular sector partitioning method is first defined with reference to the earth axis of the programmable ellipsoidal coded metrological reference target 2. This model is as follows: Figure 3 As shown in a) and b) in the figure. Take a point on the Earth's axis and draw a line from that point to the Earth's surface. The spherical region covered by the line is called an equiangular sector. The vertex of the equiangular sector is located on the Earth's axis, the angle between its two boundary lines is constant, and the plane containing the equiangular sector is parallel to the equatorial plane.

[0069] Define the following parameters:

[0070] 1) =6.371 m is the scaled-down Earth radius (corresponding to the real Earth 6371 km).

[0071] 2) =0.645 m is the scaled-down orbital altitude (corresponding to the actual orbital altitude of 645 km);

[0072] 3) This is the maximum coverage width of the camera at the equator, i.e., the arc length of the equiangular sector corresponding to the geocentric point. This arc length is determined by the camera's field of view angle. Maximum lateral sway angle and scaled-down orbital height The decision is:

[0073]

[0074] Then the geocentric angle corresponding to the equiangular sector at the Earth's center for:

[0075]

[0076] At any latitude At that point, the arc length of the line where the equiangular sector intersects the Earth's surface. satisfy:

[0077]

[0078] This can be extended to great circle trajectories with arbitrary inclination. We define the meridian as the satellite's flight direction (similar to a meridian), and the sagitta as the great circle perpendicular to the meridian, i.e., the direction of coverage width measurement (similar to a parallel of latitude). In the aforementioned sun-synchronous orbit, the satellite's position can be uniquely determined by its geographical latitude φ. In any great circle orbit, we introduce an angular coordinate (i.e., angular distance value) δ along the trajectory, which is the geocentric angle traversed by the satellite as it moves along the great circle from the intersection of its flight trajectory and the equator. Figure 3 In , , These are schematic diagrams used to represent the arc lengths of the intersection lines between the isoangular sector and the Earth's surface at different latitudes.

[0079] When the satellite flies to a position with an angular distance of δ from the equator, the coverage width for:

[0080]

[0081] in, This is the angular distance value. ∈[−π / 2,π / 2], corresponding to the complete arc segment of the satellite's motion across the poles along its great circle trajectory. This formula does not depend on the specific inclination of the orbit or the longitude of the ascending node, and therefore applies to satellites in all orbits.

[0082] Step 2: Grid image acquisition and strip edge processing;

[0083] Before the experiment begins, the system is calibrated: the camera of the spatiotemporally synchronized trigger image acquisition unit 3 is driven to slowly traverse the entire arc-shaped guide rail. The screen remains still, and the camera continuously acquires images of coded marker points. According to the trajectory defined in step 1, the device renders the meridian and sagittal line on the sphere in real time and displays coded points at equal intervals in the sagittal direction to form a dynamic coordinate system and establish a mapping table.

[0084] The camera's position is fixed at the tilt angle of the arc-shaped guide rail of the motion module 5. The camera then begins to move along the arc-shaped guide rail. The current angular distance... The yaw angle control curve is calculated in real time by the motion control system. It is parameterized using discrete nodal spline interpolation: selected within the δ interval [0, π / 2]. There are nodes, and the angular distance values ​​of the corresponding nodes are represented as δ1, δ2, ..., δ. M Corresponding lateral swing angles θ1, θ2, ..., θ M The θ(δ) curve is generated by cubic spline interpolation.

[0085] This implementation method uses a set of initial parameters for experimentation: setting node initialization. The cooperative controller drives the camera from... At point =π / 2, a constant velocity v = 7.07 mm / s is directed towards... =0, and at the same time according to the current Interpolation is used to calculate the target's side swing angle, driving the sweeping device to adjust the camera's attitude in real time. An ellipsoidal digital array dynamically displays a dynamic mesh on the screen. The camera rolls at a constant angular velocity. It continuously acquires images at a fixed frame rate, and each frame includes a timestamp, the position of the guide rail slider, the swing angle feedback value, and the scrolling phase displayed on the screen using an ellipsoidal digital array.

[0086] Subsequently, coded point identification is performed on each frame of the image, and the sagittal angle range covered by that frame of the image is calculated using the established calibrated mapping table. Angular distance range ,in These represent the minimum and maximum camera field of view, respectively. These represent the minimum and maximum angular distance values, respectively. The surface of the ellipsoidal digital array dynamic display screen is pre-discrete into equally spaced grids. , The camera field of view interval, Each grid cell has a unique angular range and a known spherical area, with angular distance values ​​as intervals. The device marks all grid cells within the frame's coverage area as "covered" and records the number of times each grid cell is covered.

[0087] Step 3: Calculate coverage and overlap rates;

[0088] Each grid cell on the target surface of programmable ellipsoidal coded metrological reference target 2 The corresponding angle range is , Area of ​​each grid cell for:

[0089]

[0090] in, and These represent the row and column indices of the grid cell, respectively. For the first The corresponding camera field of view, For the first The corresponding camera field of view, For the first The angular distance value between the corresponding satellite and the intersection of the equator. For the first The angular distance between the corresponding satellite and the point where the equator intersects;

[0091] The sum of the areas of all grid cells equals the total area of ​​the sphere. .

[0092] During the actual scan, coded points are identified for each frame of image, the covered grid range is calculated, and all grid cells within the range are marked as "covered". After the scan is completed, the union of the actually covered grid cells is calculated. Its area for:

[0093]

[0094] Define the coverage of this transit. for:

[0095]

[0096] when When the coverage is 100%, the actual coverage width is exactly equal to the theoretical gauge, and the strips will be seamlessly spliced ​​after multiple cycles of regression; when When the coverage is less than 100%, it indicates that the actual coverage width during camera scanning is insufficient, and gaps will appear in the strip after multiple scans; when When it exceeds 100%, there is overlap and waste.

[0097] For the superposition effect of the actual scanning range after continuous transit in this embodiment, please refer to [link / reference]. Figure 4 .

[0098] The coverage during the experiment was affected by a combination of factors such as servo system response error and track speed fluctuation. Seamless splicing was ensured by adjusting the relevant parameters.

[0099] For a stripe with a given angular distance interval, define the overlap rate. The number of grid cells within this strip that are covered ≥ 2 times. The total number of covered grid cells within the strip The ratio:

[0100]

[0101] 0< <30% is considered a reasonable range, and a moderate overlap is retained to ensure the reliability of strip edge splicing; when When the overlap is greater than 30%, it is considered to be relatively serious, which means that the sweep angle is too large or the parameter control is too conservative, resulting in data redundancy and resource waste.

[0102] Finally, the device outputs curves showing the coverage rate as a function of angular distance, and curves showing the overlap rate as a function of angular distance, which can visually display the distribution of control error.

[0103] Step 4: Parameter optimization;

[0104] Operators set optimization goals, specifying acceptable coverage and overlap ranges, and automatically iterate through preset search ranges of relevant parameters under these constraints, for example:

[0105] Maximum sweep angle θ max The angle increases from 10° to 40° in fixed increments of 0.1°.

[0106] Types of sweep angle curves: θ(φ), linearly decreasing, constant, etc.;

[0107] Orbital velocity V S : 6~8 mm / s, increasing in fixed steps of 0.1 mm / s;

[0108] Oscillation frequency: 0.5~5Hz, step size 0.5 Hz;

[0109] The device automatically generates a list of parameter combinations and executes steps 2 and 3 sequentially according to the list of parameter combinations, recording the cumulative coverage and overlap rate for each set of parameters. After the traversal is completed, all parameter combinations that meet the coverage target are selected and sorted according to the priority of "highest cumulative coverage, fewest crossings, and overlap rate closest to the target median". The device outputs the optimal scanning parameter scheme, the optimal sweep angle curve, and the corresponding coverage performance report.

[0110] This embodiment fully demonstrates that the device proposed in this invention has a clear structure and a well-defined process. It successfully integrates a scaled-down physical model, a dynamic coordinate system based on angular distance, and spline parameterized side swing angle control into one system. This not only enables precise measurement of transit coverage effectiveness but also experimentally verifies the equiangular sector coverage law under arbitrary large circular arc trajectories, providing a complete ground verification and parameter optimization scheme for global seamless and rigorous splicing tasks.

[0111] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device, characterized in that, include: Motion simulation unit, programmable ellipsoidal coded metrological reference target, spatiotemporal synchronous triggered image acquisition unit, and coverage performance evaluation and optimization unit; The motion simulation unit includes: an orbital motion module, a scanning motion module, and an orbital tilt adjustment structure; a spatiotemporally synchronized triggered image acquisition unit is set on the scanning motion module; the scanning motion module is set on the orbital motion module; the orbital tilt adjustment structure is connected to the orbital motion module and is used to adjust the tilt angle of the orbital motion module; the orbital motion module is set on the periphery of the programmable ellipsoidal coded metrological reference target; Programmable ellipsoidal coded metrological reference targets are used to simulate the longitude drift of sub-satellite points caused by the Earth's rotation; The scanning motion module is used to drive the spatiotemporally synchronized triggered image acquisition unit to reciprocate and swing, simulating the working mode of the on-board camera's sweeping motion. The spatiotemporally synchronized triggered image acquisition unit works in coordination with the orbital motion module and the scanning motion module to acquire local images of the programmable ellipsoidal coded metrological reference target in real time, and transmits the target image with position coding information to the coverage performance evaluation and optimization unit in real time. The coverage performance evaluation and optimization unit is used to receive target images and real-time trajectory data from the motion simulation unit, and to calculate the grid coordinate region corresponding to each frame of image through image recognition algorithms, thereby reconstructing the continuous sweep trajectory of the instantaneous field of view on the sphere.

2. The space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device according to claim 1, characterized in that, The spatiotemporal synchronized triggered image acquisition unit is a global shutter CMOS camera.

3. The space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device according to claim 1, characterized in that, The track motion module includes: an arc-shaped guide rail and a guide rail slider; the arc-shaped guide rail is in the shape of a ring; the guide rail slider is set on the arc-shaped guide rail; the guide rail slider moves at a constant speed along the arc-shaped guide rail.

4. The full-domain equiangular sector-shaped tight splicing device for space-based dynamic vertical rail scanning according to claim 3, characterized in that, The scanning motion module is driven by a voice coil motor, with the swing shaft perpendicular to the plane of the arc-shaped guide rail. The maximum swing angle is ±30°, and the swing angle control accuracy is better than 0.01°.

5. The space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device according to claim 1, characterized in that, The track motion module and the scanning motion module are uniformly scheduled by the coordinated controller and can be independently adjusted or operated in conjunction with each other according to the set speed, swing amplitude, and frequency.

6. The space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device according to claim 1, characterized in that, The coverage performance evaluation and optimization unit is also used to, when a specified area is fully covered or the overlap rate is not lower than a certain threshold within a certain number of passes, traverse the combination of scanning amplitude, oscillation frequency, and orbital speed parameters, run the simulation multiple times and record the corresponding coverage performance indicators, and finally output the optimal scanning parameter scheme that meets the task constraints.

7. The space-based dynamic vertical rail scanning full-domain equiangular sector-shaped tight splicing device according to claim 1, characterized in that, The target surface of the programmable ellipsoidal coded metrological reference target displays a grid and location coded markers. The grid rolls westward at the Earth's rotational angular velocity. Each grid cell has unique location coordinates, and the coded markers at the boundaries of adjacent grids are automatically identified and located by a spatiotemporally synchronized triggered image acquisition unit.

8. A method for full-area equiangular sector-shaped tight stitching of space-based dynamic vertical rail scanning, applicable to the full-area equiangular sector-shaped tight stitching device for space-based dynamic vertical rail scanning as described in claim 1, characterized in that, Includes the following steps: Step 1: Theoretical model establishment and initial parameter calculation; Take a point on the Earth's axis of the programmable ellipsoidal coded metrological reference target, and draw a line from that point to the Earth's surface. The spherical region covered by the line is called an equiangular sector. The vertex of the equiangular sector is located on the Earth's axis, the angle between its two boundary lines is constant, and the plane containing the equiangular sector is parallel to the equatorial plane. Define the following parameters: This is the scaled-down radius of the Earth. This is the scaled-down orbital height; Let be the arc length of the equiangular sector corresponding to the geocentric point, which is determined by the camera's field of view angle. Maximum lateral sway angle and scaled-down orbital height The decision is: Then the geocentric angle corresponding to the equiangular sector at the Earth's center for: At any latitude At that point, the arc length of the line where the equiangular sector intersects the Earth's surface. satisfy: When the satellite flies to a position with an angular distance of δ from the equator, the coverage width for: ;in, This is the angular distance value. ∈[−π / 2,π / 2]; Step 2: Grid image acquisition and strip edge processing; The drive time-space synchronous triggering image acquisition unit travels the entire path along the track motion module. The screen image remains still, continuously acquiring images of coded marker points. According to the trajectory defined in step 1, the device renders the meridian and sagittal line on the sphere in real time, and displays coded marker points at equal intervals in the sagittal direction, forming a dynamic coordinate system and establishing a mapping table. Step 3: Calculate coverage and overlap rates; Each grid cell on the target surface of a programmable ellipsoidal coded metrological reference target The corresponding angle range is , Area of ​​each grid cell for: in, and These represent the row and column indices of the grid cell, respectively. For the first The corresponding camera field of view, For the first The corresponding camera field of view, For the first The angular distance value between the corresponding satellite and the intersection of the equator. For the first The angular distance between the corresponding satellite and the point where the equator intersects; The sum of the areas of all grid cells equals the total area of ​​the sphere. ; After the transit ends, the actual grid cells covered are counted and combined. Its area for: Define the coverage of this transit. for: For a stripe with a given angular distance interval, define the overlap rate. The number of grid cells within this strip that are covered ≥ 2 times. The total number of covered grid cells within the strip The ratio: The curves showing the device output coverage as a function of angular distance, and the curves showing the overlap rate as a function of angular distance; Step 4: Parameter optimization; Set optimization goals, give acceptable coverage and overlap ranges, and automatically traverse the preset search range of relevant parameters under these constraints; The device automatically generates a list of parameter combinations and executes steps 2 and 3 sequentially according to the list of parameter combinations, recording the cumulative coverage and overlap rate for each set of parameters. After the traversal is completed, all parameter combinations that meet the coverage target are selected and sorted according to the priority of the highest cumulative coverage rate, the fewest number of passes, and the overlap rate closest to the target median. The device then outputs the optimal scanning parameter scheme, the optimal sweep angle curve, and the corresponding coverage performance report.

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