A Large-Scale Scheduling Method for Multiple Agile Optical Satellites

This study investigates the scheduling problem ofmultiple agile optical satelliteswith large-scale tasks.This problem is difficult to solve owing to the time-dependent characteristic of agile optical satellites,complex constraints,and considerable solution space.To solve the problem,we propose a scheduling method based on an improved sine and cosine algorithm and a task merging approach.We first establish a scheduling model with task merging constraints and observation action constraints to describe the problem.Then,an improved sine and cosine algorithm is proposed to search for the optimal solution with the maximum profit ratio.An adaptive cosine factor and an adaptive greedy factor are adopted to improve the algorithm.Besides,a taskmerging method with a task reallocation mechanism is developed to improve the scheduling efficiency.Experimental results demonstrate the superiority of the proposed algorithm over the comparison algorithms.

The output torque estimation of MCMG for agile satellites

Studied in this paper are the attitude control law design and the output torque estimation problem of micro control moment gyros （MCMGs） for the agile satellites executing rapid attitude maneuver mission. An algorithm is proposed for estimating the output torques and the gimbal angular rates of MCMGs, which can help engineers to choose reasonable size for actuators so that the cost of satellite can be decreased. According to some special maneuver missions, a numerical example of attitude control system for a small satellite with MCMGs in pyramid configuration is studied, and the simulation results validate the proposed estimation algorithm.

Improved algorithms to plan missions for agile earth observation satellites

This study concentrates of the new generation of the agile （AEOS）. AEOS is a key study object on management problems earth observation satellite in many countries because of its many advantages over non-agile satellites. Hence, the mission planning and scheduling of AEOS is a popular research problem. This research investigates AEOS characteristics and establishes a mission planning model based on the working principle and constraints of AEOS as per analysis. To solve the scheduling issue of AEOS, several improved algorithms are developed. Simulation results suggest that these algorithms are effective.

Real-time online rescheduling for multiple agile satellites with emergent tasks

The emergent task is a kind of uncertain event that satellite systems often encounter in the application process.In this paper,the multi-satellite distributed coordinating and scheduling problem considering emergent tasks is studied.Due to the limitation of onboard computational resources and time,common online onboard rescheduling methods for such problems usually adopt simple greedy methods,sacrificing the solution quality to deliver timely solutions.To better solve the problem,a new multi-satellite onboard scheduling and coordinating framework based on multi-solution integration is proposed.This method uses high computational power on the ground and generates multiple solutions,changing the complex onboard rescheduling problem to a solution selection problem.With this method,it is possible that little time is used to generate a solution that is as good as the solutions on the ground.We further propose several multi-satellite coordination methods based on the multi-agent Markov decision process(MMDP)and mixed-integer programming(MIP).These methods enable the satellite to make independent decisions and produce high-quality solutions.Compared with the traditional centralized scheduling method,the proposed distributed method reduces the cost of satellite communication and increases the response speed for emergent tasks.Extensive experiments show that the proposed multi-solution integration framework and the distributed coordinating strategies are efficient and effective for onboard scheduling considering emergent tasks.

Mission Planning and Action Planning for Agile Earth-Observing Satellite with Genetic Algorithm

This paper concerns the mission scheduling problem for an agile Earth-observing satellite. Mission planning and action planning for the satellite are both taking into account. Multiple mission types( including multi-strip area,real time download request,and stereoscopic request) and complex satellite actions,such as observe action and data download action,are considered in this paper. Through reasonable analysis of specialties and operational constraints of agile satellites in observing process,the mission scheduling model under multiple objective conditions is constructed. A genetic algorithm combined with heuristic rules is designed to solve problem. Genetic algorithm is designed to arrange user missions and heuristic rules are used to arrange satellite actions. Experiment results suggest that our algorithm works well for the agile Earth-observing satellite scheduling problem.

Agile Satellite Mission Planning via Task Clustering and Double-Layer Tabu Algorithm

Satellite observation schedule is investigated in this paper.A mission planning algorithm of task clustering is proposed to improve the observation efficiency of agile satellite.The newly developed method can make the satellite observe more targets and therefore save observation resources.First,for the densely distributed target points,a preprocessing scheme based on task clustering is proposed.The target points are clustered according to the distance condition.Second,the local observation path is generated by Tabu algorithm in the inner layer of cluster regions.Third,considering the scatter and cluster sets,the global observation path is obtained by adopting Tabu algorithm in the outer layer.Simulation results show that the algorithm can effectively reduce the task planning time of large-scale point targets while ensuring the optimal solution quality.

Attitude control for part actuator failure of agile small satellite

The stability and singularity problem of agile small satellite （ASS） with actuator failure is discussed in this paper. Firstly, the three-axis stabilized controller of an ASS is designed, where micro control moment gyros （MCMG＇s） in pyramid configuration （PC） is used as the actuator. By using the same controller and steering law, the control results before and after one gyro fails are compared by simulation. The variation of singular momentum envelope before and after one gyro fails is also compared. The simulation results show that the failure intensively decreases the capacity of output torque, which leads to the emergence of more singular points and the rapid saturation of MCMG＇s. Finally, the parameters of system controller are changed to compare the control effect.

Enabling Technologies for Agile Maritime Communication Networks

With the rapid development of maritime activities,there has been a growing demand for high data rate and ultra-reliable maritime communications.Traditionally,this is provided by maritime satellites.Besides,shore and island-based base stations(BSs)can be built to extend the coverage of terrestrial networks providing the fourth-generation(4G)or even the fifth-generation(5G)services.Unmanned aerial vehicles(UAVs)-aided and ship-borne BSs can also be exploited to serve as relaying nodes in maritime mesh/ad-hoc networks.Despite all these approaches,there are still open issues towards the establishment of an agile maritime communication network(MCN).

面向重访周期需求的敏捷成像卫星任务规划方法

为满足敏捷成像星座观测目标的重访周期需求,提出一种混合编码差分进化算法.分析敏捷成像卫星的工作特点,构造评价重访周期需求满足情况的目标函数,建立成像任务约束满足模型.针对观测任务选择与否、执行顺序和成像时间的优化需求,提出一种二进制-实数混合编码差分进化算法,实现了成像任务在时间轴上的分布优化.通过工程实例进行仿真校验,仿真结果表明相比于基于二进制编码的遗传算法,本文算法在优化时间和优化效果方面都有较大优势.

一种面向在轨服务卫星地面应用系统的软件开发方法

为解决现有在轨服务卫星地面应用系统瀑布式软件开发模型灵活性差,难以适应用户需求变化等不足,通过利用敏捷开发模型的思路,设计了一种迭代式在轨服务卫星地面应用系统软件开发方法,将用户纳入到软件开发过程中,在各个研制阶段持续与用户进行需求迭代,完成业务软件的功能升级。结果表明:该方法可提升业务软件功能与用户需求的匹配程度,并为后续在轨服务卫星地面应用系统的建设提供参考。

光学遥感卫星精密敏捷成像控制技术综述

从控制的角度综述了多功能、高质量成像需求下,超稳定、超精确、超敏捷高分辨率光学遥感卫星精密敏捷控制的关键技术和研究进展。以卫星成像与姿态控制系统性能的关系为基础,从姿态机动能力与多功能成像、姿态确定精度与成像质量和姿态控制精度与成像质量三个方面论述了精密敏捷控制技术对光学遥感卫星成像的重要性。在此基础上,结合光学遥感卫星姿态控制系统的组成及原理,分析了影响姿态控制精度和姿态机动能力的主要因素,对高精度姿态确定、精密姿态控制和敏捷姿态控制三个关键技术方向进行了讨论和总结。最后,综合当前技术的发展趋势,围绕一体化成像控制的设计思想展望了精密敏捷控制技术未来的发展趋势,为实现高分辨率光学遥感卫星多功能、高质量成像控制提供了理论依据和工程参考。

A rapid method for validation and visualization of agile Earth-observation satellites scheduling

This paper describes a rapid method for validation and visualization of agile Earth-observation satellites scheduling.Benefited from the previous work,various algorithms are proposed for scheduling the observations of agile satellites.However,the satellite maneuvers are three-dimensional,this characteristic makes it difficult for the operation engineers to validate and interpret the scheduled solutions.They have to plot these attitude data to analyze different situations such as an observing phase or a slew maneuver.Finally,one tries to imagine the three-dimensional situations from many one-dimensional plots,which is time-consuming and susceptible to errors.Moreover,now it is low-efficiency to deal with the data about ephemeris,targets,etc.,because different software platforms are required.In this research,a validation and visualization method is suggested to overcome this barrier.It is successful to integrate the Satellite Tool Kit ActiveX and the C#programming language.Based on the embedded scheme,all the interaction and assessment can be visualized.Practical techniques for modelling satellite objects,sensor objects,target objects and satellite attitudes are presented.Such a method has been applied for Chinese agile satellites project,and a software interface has been developed.The simulation results indicate that the proposed method is intuitive and efficient.Note that this method is general,and thus it can be applied to other Earth observation missions.Enough details are provided for interested readers to develop the software interface.

北京三号A/B卫星总体设计及技术创新

北京三号A/B卫星是基于我国第二代敏捷卫星平台CAST3000E研制的高分辨率光学遥感智能敏捷卫星,具有“超敏捷、超稳定、超精度”、“智能复合控制、智能自主规划、智能图像处理”的技术特点。文章重点介绍了北京三号A/B卫星的总体设计和技术创新性,包括卫星设计方案、成像模式和操控模式等,并结合在轨实际应用情况介绍了卫星的能力水平及技术指标的国际对标情况。

敏捷卫星动中成像自主任务规划算法

针对敏捷卫星动中成像(APBI)自主任务规划所涉及的关键算法进行了研究。首先,基于载荷幅宽和卫星轨道设计了区域目标斜条带拼幅成像垂轨条带划分算法;其次,建立了描述观测点位置与成像时间关系的连续可导的斜条带成像轨迹模型,进而推导出了敏捷卫星动中成像的三轴姿态规划算法;再次,为了发挥出卫星的最大机动能力,提出了一种基于六阶多项式姿态机动模型的动中成像任务间最短姿态机动时间求解算法;然后,设计了兼顾观测效率与质量的两级任务优化调度算法,包括基于分支定界算法与两种裁剪枝规则的及早观测搜索和观测队列最佳窗口倒序平移,在最大化观测目标数量的基础上将成像质量调整到最优;最后,在星载处理器上进行了仿真实验,仿真结果证明了本文所提算法的正确性和有效性。

基于聚类变异PSO优化的VSCMGs模糊平滑切换算法

针对变速控制力矩陀螺(variable speed control moment gyro,VSCMG)作为执行机构应用在敏捷遥感卫星上进行姿态机动时末端模式切换的平稳性和快速性冲突问题,在考虑框架转速误差的基础上,设计姿态误差参数作为切换指标,制定误差参数切换区域内的过渡规则,将指令力矩实时分配给控制力矩陀螺(control moment gyro,CMG)和飞轮并分别求解,提出了一种控制力矩陀螺/反作用飞轮工作模式模糊平滑切换操纵律。为了使得姿态机动末端卫星姿态达到姿态稳定度和指向精度要求的时间更短,以该时间为优化指标提出聚类变异改进粒子群算法对该操纵律参数寻优,确定最佳的切换区域和切换参数,并进行了仿真验证。结果表明:改进后粒子群算法在相同的迭代次数中总是表现出比传统粒子群算法更优的适应度,具有更快的收敛速度和更高的收敛精度,参数优化后的模糊平滑切换操纵律相比于现有操纵律能够在较短时间内完成双模式的平滑切换,并在姿态机动末端更迅速地达到姿态稳定度和指向精度要求,提高了遥感卫星敏捷机动与高稳指向的控制性能,有利于高质量完成成像任务。

天基遥感中航天器挠性对成像区域的影响

针对遥感敏捷卫星机动模式对地成像观测,分析挠性附件振动对卫星成像区域和质量的影响。首先利用有限元法和拉格朗日法建立带挠性附卫星的动力学模型;然后通过星地几何法计算成像条带;最后分别选取太阳同步轨道和地球同步轨道,以两个对称的太阳能帆板作为挠性附件,给出数值仿真结果。仿真结果表明,卫星机动完成后,成像区域横滚方向与俯仰方向均偏差较大,导致成像区域错位;太阳帆板振动对成像区域的影响随着其振动减弱而减弱,并逐渐趋于稳定。卫星轨道高度越高,扰动对于卫星成像区域的影响越大,需要更长时间稳定自身姿态。

Agile Earth Observation Satellite Scheduling Algorithm for Emergency Tasks Based on Multiple Strategies

During the execution of imaging tasks,satellites are often required to observe natural disasters,local wars,and other emergencies,which regularly interferes with the execution of existing schemes.Thus,rapid satellite scheduling is urgently needed.As a new generation of three degree-of-freedom(roll,pitch,and yaw)satellites,agile earth observation satellites(AEOSs)have longer variable-pitch visible time windows for ground targets and are capable of observing at any time within the time windows.Thus,they are very suitable for emergency tasks.However,current task scheduling models and algorithms ignore the time,storage and energy consumed by pitch.Thus,these cannot make full use of the AEOS capabilities to optimize the scheduling for emergency tasks.In this study,we present a fine scheduling model and algorithm to realize the AEOS scheduling for emergency tasks.First,a novel time window division method is proposed to convert a variable-pitch visible time window to multiple fixed-pitch visible time windows.Second,a model that considers flexible pitch and roll capabilities is designed.Finally,a scheduling algorithm based on merging insertion,direct insertion,shifting insertion,deleting insertion,and reinsertion strategies is proposed to solve conflicting problems quickly.To verify the effectiveness of the algorithm,48 groups of comparative experiments are carried out.The experimental results show that the model and algorithm can improve the emergency task completion efficiency of AEOSs and reduce the disturbance measure of the scheme.Furthermore,the proposed method can support hybrid satellite resource scheduling for emergency tasks.

面向卫星多目标重复观测任务的分层聚类规划

针对敏捷卫星多目标重复观测任务规划面临的可行任务执行序列集合规模庞大困难,提出了一种任务执行序列时间解耦的分层聚类任务规划方法。该方法以规划过程中的可观测窗口和任务执行窗口为聚类对象,通过单次可观测窗口聚类和多次任务执行窗口聚类将任务集合按任务窗口属性分解为一系列时间解耦的小规模集合,在两次任务执行窗口聚类间使用基于贪婪优化的搜索算法对聚类生成的小规模任务集合分别进行集合内任务规划,最后将各集合的任务规划结果合并后得到所有任务的执行序列。仿真结果表明,该分层聚类方法可有效降低全局优化复杂度,消解不同优先级观测任务的冲突,提高任务规划质量,能够在不降低目标点观测完成率的前提下对有多个观测机会的目标点进行重复观测,且算法稳定性好,能在数秒内得出规划结果,适用于星上自主任务规划。

基于TVNS的敏捷对地观测卫星自主动作规划算法

针对敏捷对地观测卫星自主动作规划问题,建立了基于时间线约束网络的问题模型。通过对模型的分析,归纳出9种卫星动作序列,确定了各种动作序列之间的衔接关系,并在此基础上设计了动作时间的计算和调整方法,提出了基于三阶段变邻域搜索(Three-stage Variable Neighborhood Search, TVNS)的敏捷对地观测卫星自主动作规划算法。算法以任务调度结果作为初始解,分3个阶段,使用2种邻域结构进行变邻域搜索,实现了任务到动作的转换。通过实验证明了基于TVNS的敏捷对地观测卫星自主动作规划算法的有效性。

面向体系仿真的敏捷成像卫星系统建模方法

敏捷成像卫星具有灵巧机动的优点,能够实现对观测任务的快速响应,已获得较广泛的军事应用。基于体系对抗仿真应用背景,采用组件化建模方法构建敏捷成像卫星平台模型、卫星机动组件模型、光学成像传感器组件模型、通信设备组件模型,设计构建卫星地面站模型以及基于任务动态插入的敏捷成像卫星地面任务系统模型。在集成敏捷成像卫星系统仿真系统的基础上,通过仿真试验验证所构建的敏捷成像卫星系统模型能够实现自动化成像任务编排,可模拟敏捷成像侦察过程,有效地支撑卫星作战运用背景下的体系对抗仿真需求。