CN-121973957-A - Satellite area coverage discrete optimization and attitude maneuver planning method with turntable

CN121973957ACN 121973957 ACN121973957 ACN 121973957ACN-121973957-A

Abstract

A satellite area coverage discrete optimization and attitude maneuver planning method with a turntable belongs to the technical field of satellite application and observation planning. According to the method, the optimal strips with the maximum area coverage rate are obtained by area grid division and candidate strip set generation in any direction through integer programming modeling solution. According to the invention, a two-dimensional turntable corner sequence meeting the pointing constraint and the speed parallel constraint is planned, and based on the minimum Euler rotation, the body gesture quaternion track of the satellite executing strip push-broom imaging is deduced and obtained. And for gesture directional switching between strips, performing quaternion spherical linear interpolation on the initial quaternion and the target quaternion by designing Euler rotation angular velocity tracks to obtain continuous and rapid gesture maneuvering tracks. The regional coverage discrete optimization and attitude maneuver planning method allows the generation of the optimized coverage strips in any direction, reduces the regional coverage attitude maneuver gap and improves the execution efficiency of the observation task.

Inventors

XU RUI
ZHU ZHE
LI CHAOYU
WANG BANG
ZHU SHENGYING
LIANG ZIXUAN

Assignees

北京理工大学

Dates

Publication Date: 20260505
Application Date: 20260203

Claims (9)

1. The satellite area coverage discrete optimization and attitude maneuver planning method with the turntable is characterized by comprising the following steps of: Step1, realizing ground observation region division through discrete optimization design of strips, discretizing the region into grid cells, generating a candidate strip set, and selecting from candidate strips An optimal coverage strip for achieving complete coverage of the grid cells within the area, wherein The minimum strip number is obtained through iterative optimization; Step 2, push-broom is carried out along the optimized strip generated in the step 1, pointing tracking is kept, a push-broom imaging attitude maneuver planning method is provided, a two-dimensional turntable corner sequence meeting pointing constraint and speed parallel constraint is solved, and based on minimum Euler rotation, a body attitude quaternion track of a satellite executing strip push-broom imaging is deduced; And 3, designing Euler rotation angular velocity tracks based on the stripe push-broom imaging pose maneuver sequence obtained in the step 2, providing a stripe switching rapid maneuver planning method, solving an initial quaternion and a target quaternion in the stripe switching process, and obtaining stripe switching pose maneuver quaternion tracks through quaternion spherical linear interpolation, namely realizing discrete optimization of satellite area coverage with a turntable and pose maneuver planning.
2. The method of claim 1, wherein the discretizing the region into grid cells in step 1 is, For a polygonal ground observation target area, extracting a boundary frame of the area according to polygon vertexes, and calculating a spatial range of the boundary frame in longitude and latitude directions, dividing a discretized grid of the polygonal ground observation target area into a group of grid units based on the spatial range, wherein each grid unit has a central longitude and latitude coordinate )。
3. The method of claim 1, wherein the generating the candidate set of strips in step 1 is performed by, Generating a candidate stripe set by traversing the samples, the candidate stripe set being a set of candidate stripes having various directions and offsets; Sampling the offset perpendicular to the strip direction with a length offset for each direction, producing a plurality of candidate strips, the union of which can cover the polygonal target area and slightly exceed the bounding box of the area; To estimate the coordinates as Whether or not a unit is covered by a candidate stripe Overlay, two endpoints defining a stripe centerline Calculating unit coordinates With the center line of the passing strip Is the distance between the straight lines of (2)
4. If the distance is less than or equal to the projected half-width of the candidate strip The unit is considered to be covered by the candidate strip, each candidate strip containing attribute information according to the above calculation, 1) the angle of direction, 2) the offset perpendicular to the strip direction, 3) the strip centerline endpoint 4) All grid cell indexes covered by the strip, in this step, generating The candidate stripes.
5. The method of claim 1, wherein the selecting of the best coverage strip from the candidate strips in step 1 is, Performing discrete optimization solution based on an integer programming model according to the target area grid unit and the candidate strip set to obtain an optimal strip observed by the target area; 1) Decision variables Defining a band selection variable: if candidate strips Is selected to Otherwise ; Definition unit coverage variable: if a unit Covered by at least one strip Otherwise The total variable number is A binary variable; 2) Objective function An objective function is defined as the total number of grid cells that maximize coverage; 3) Constraint conditions Constraint conditions include three classes, one of which is a cardinality constraint I.e. must choose A strip; The second is that the overlay contains constraints Wherein the method comprises the steps of Is a covering unit Candidate stripes of (2) The set of the two sets, Is a strip An overlaid set of units, an overlay containing constraints meaning units Can be marked as covered only when covered by at least one strip ); The coverage including constraint can be converted into matrix form For a coverage matrix, wherein: The constraint becomes: thirdly, the binary decision variable meets the binary constraint 4) Complete integer programming model solution Solving for the integer programming model, the final discrete optimization solution comprising the steps of Obtaining an optimized band set selected from candidate bands, and selecting the optimized band set from the candidate bands by Obtaining all cells covered by the optimized strips, and counting the strips Performing integer traversal from 1 from small to large until all grid cells of the target area can be covered by the optimized stripe set obtained by discrete optimization solution And (3) an optimal stripe set formed by stripes is an optimal stripe division result for realizing complete coverage of the target area.
6. The method according to claim 1, wherein the push-broom imaging pose maneuver planning method in step 2 is that, Using the ECEF definition of the geocentric fastening coordinate system 、 And under the definition of the geocentric inertial coordinate system ECI To describe the centerline of the optimized strip, Is longitude and latitude coordinates in ECEF , And Cartesian coordinates in ECEF and ECI, respectively, defining the ECI For satellite presence by orbit recursion A time interval of push scan imaging stage of each optimized band is given, and time variable Ranging from To the point of ; The first is the orientation constraint, and the satellite optical axis, namely the Z axis of the satellite body system, is always oriented under the condition of not considering the two-dimensional turntable The other is a velocity parallel constraint that requires that the projection of the optimized stripe centerline onto the satellite camera plane must always coincide with the center column of the camera field of view, i.e. the push-broom maneuver velocity of the satellite optical axis must be as in ECEF Is coincident with the tangent line of (a); Definition slave Pointing to Is a normalized vector of (2) To meet the directional constraint, the Z axis of the satellite system is along the vector Alignment, two components of the three-axis pose are determined: Wherein the method comprises the steps of Sine function for simplified representation , Cosine function for simplified representation , Representing phase corrected ; Residual component for three-axis pose According to the speed parallel constraint, in the case of satellite body maneuver, the body Y-axis must be perpendicular to the target point edge at any time during push-broom The speed of movement; The solution is as follows: Wherein the method comprises the steps of Is the rotation angle of the earth Based on the optimized stripe push-broom imaging process, euler angle is used for representing Is adopted by the theoretical triaxial attitude of the satellite Sequentially, converting into a satellite theoretical triaxial attitude represented by a quaternion: Wherein any quaternion Is formed by scalar part Sum vector part Combining the vectors representing and modulo 1, describing the rotation from ECI to satellite body; considering the two-dimensional turntable, and according to the satellite theory three-axis attitude quaternion Solving actual satellite body quaternion And two-dimensional turntable corner A time-varying sequence; defining minimum Euler rotation quaternion of satellite body The quaternary numbers are expressed as follows: Wherein the method comprises the steps of Representing the smallest euler axis of rotation of the body, Representing the minimum euler angle of the body, Representation of Is provided with a maximum swing angle of (a), Is the main shaft of the rotatable cone, i.e. zero position, of the turntable, and the known satellite observation is directed to the path , Is under inertial system camera Pointing at the moment; the satellite initial attitude quaternion is , Moment satellite body attitude quaternion Can be expressed as: Based on inertial system Time of day camera pointing , Is corresponding to quaternion Is used for calculating the camera pointing direction under the satellite system By taking into account the two-dimensional turntable Deriving a sequence of two-dimensional turntable rotation angle changes with time : Taking a two-dimensional turntable corner sequence as a nominal sequence, and using quaternion multiplication and sum Corresponding rotation matrix Deriving a satellite body quaternion sequence meeting the pointing constraint and the speed parallel constraint; definition of quaternions Is a quaternion Is represented by the conjugate of By rotating the matrix Conversion to quaternion expressions And further take its conjugated quaternion Satellite body quaternion meeting pointing constraint and speed parallel constraint is calculated by using quaternion multiplication : Wherein the quaternion multiplication symbol is' ", Represents the superposition of the rotations described by the two quaternions; The push-broom imaging attitude maneuver planning method plans to obtain the body triaxial attitude maneuver sequence with turntable satellite expressed by quaternion in the push-broom imaging process And two-dimensional turntable corner sequence 。
7. The method of claim 1, wherein the fast maneuver for switching the stripes in step 3 is, For the strip switching process from the last strip to the next strip, the end quaternion of the body position maneuver sequence of the last strip is The initial quaternion of the body attitude maneuver sequence of the next strip is Thus, the initial quaternion and the target quaternion of the stripe switching gesture maneuvering process are And Euler rotation angular displacement for stripe switching Calculated by dot product: the angular velocity integration yields the euler rotation angle of the current pose relative to the initial pose at each moment, and therefore, Euler angular displacement at time The Euler rotation angular velocity trajectory can be obtained by integrating Euler rotation angular velocity trajectories; Is a piecewise function; Wherein the method comprises the steps of ; Based on Euler rotation angle displacement, in initial quaternion And a target quaternion Performs a spherical linear interpolation Slerp between them, The quaternion interpolation of the time is: By performing this interpolation for each instant, an analytical function is determined Then, obtaining the motorized quaternion track of the strip switching gesture 。
8. The method according to claim 6, wherein the Euler rotational angular velocity trajectory is, In the strip switching stage between adjacent optimized strip push-broom observation tasks, the strip switching gesture maneuvering process executes the trapezoidal Euler rotation angular velocity track, and the time interval of strip switching is set as a fixed time interval In order to avoid abrupt changes in angular velocity at the beginning and end of the euler rotation, the duration is designed to be respectively at the beginning and end In the linear transition period of 0 to 0 During which the Euler rotational angular velocity varies linearly from 0 to In (1) To the point of During the period, euler rotation angular velocity is from Linearly change to 0, in To the point of Is kept at the Euler rotational angular velocity Thus, the Euler rotational angular velocity trajectory forms a trapezoidal curve.
9. The method of claim 1, further comprising the step of 4 generating an optimized coverage strip in any direction according to the algorithm of the step 1, the step 2 and the step 3, planning a continuous push-broom imaging and directional switching process and carrying out satellite attitude maneuver tracks of a turntable, dividing each area by the optimized strip for each satellite, and converting the geometrically divided strip lines into executable continuous maneuver tracks and contours by the attitude planning, thereby effectively reducing the area coverage attitude maneuver gaps and improving the execution efficiency of the satellite observation tasks with the turntable.

Description

Satellite area coverage discrete optimization and attitude maneuver planning method with turntable Technical Field The invention aims at a class of super-sensitive satellites with turntables to execute a coverage task of a ground observation area, relates to a discrete optimization and attitude maneuver planning method for the coverage of the satellite area with the turntables, and belongs to the technical field of satellite application and observation planning. Background Earth observation satellites are an important component of modern aerospace systems and play an irreplaceable role in tasks such as extensive monitoring, reconnaissance and environmental monitoring. With the continuous increase of the requirements for high resolution and high timeliness information, modern earth-facing observation tasks are increasingly oriented to large-range area targets with wide spatial distribution and irregular geometric shapes, and the regional observation tasks have higher requirements on the maneuverability of satellites and an observation planning method. On the basis, the rapid development of the hypersensitive satellite remarkably expands the task capacity boundary of the earth observation satellite. In recent years, the agile mobility of earth observation satellites is further improved in the aspect of load design by introducing a two-dimensional turntable. The two-dimensional turntable is generally composed of an azimuth axis and a pitching axis which are mutually orthogonal, so that the optical load can be directionally adjusted in a certain range independently of the attitude of the satellite body. The structure and performance of a two-dimensional turntable in near-earth space high-resolution observation imaging are systematically analyzed, and the turntable design enables partial pointing maneuver to be completed on a load level, so that decoupling between fine pointing control and large-angle platform-level attitude maneuver is realized to a certain extent. Compared with the traditional super-agile satellite completely relying on whole-satellite attitude redirection, the introduction of the two-dimensional turntable can obviously improve the pointing response speed and reduce the frequency and amplitude of platform-level attitude maneuver. Therefore, the satellite carrying the two-dimensional turntable can continuously carry out the direction adjustment in the imaging process, so as to support push-broom imaging in any direction. Traditional satellite regional observation planning studies typically pre-fix regional divisions or simply consider roll maneuvers and ignore tri-axial attitude capabilities, limiting their adaptability to different satellites and complex regional coverage needs. The push-broom type observation operation is carried out by the super-agile satellite carrying the two-dimensional turntable, and a strip with a certain scanning width is formed on the surface of the earth in the push-broom type observation process, so that the method is more suitable for an area coverage method modeled as strip division, and a continuous strip type observation task is carried out. The strip imaging geometry and attitude maneuver constraint conditions are explicitly considered, and the complete coverage of the region is realized by continuous attitude maneuver in the imaging process with minimum fly-through times. In the developed method for regional coverage discrete optimization and attitude maneuver planning of the satellite with the turntable, the prior art proposes that the hypersensitive satellite is a agile satellite with higher attitude angular speed and attitude angular acceleration output capability, has remarkably improved rapid attitude maneuver capability and still can keep high stability at the load end of the pointing mechanism. The ultra-sensitive satellite related research which can achieve ultra-fast mobility and high stability has important significance. The super-agile satellite with the turntable further enhances the flexibility of earth observation through integrating the two-dimensional turntable, and the prior art researches the design and the performance of the two-dimensional turntable mechanism for high-definition monitoring imaging of the near-earth space. This configuration allows the payload of a camera or the like to perform independent pointing maneuvers, effectively enabling the kinematic decoupling of fine pointing control from the wide angle satellite body maneuvers. Therefore, the super-agile satellite with the two-dimensional turntable can carry out continuous attitude pointing adjustment in the imaging process, thereby realizing complex observation modes such as scanning in any direction, multi-strip splicing, continuous push-broom imaging and the like in single orbit flight. However, the prior art research does not consider the constraint faced by the execution of push-broom imaging task by the hypersensitive satellite with the two-dimensional turntable and the co