Dynamics and control of spacecraft hovering using the geomagnetic Lorentz force

To achieve hovering, a spacecraft thrusts continuously to induce an equilibrium state at a desired position. Due to the constraints on the quantity of propellant onboard, long-time hovering around low-Earth orbits (LEO) is hardly achievable using traditional chemical propulsion. The Lorentz force, acting on an electrostatically charged spacecraft as it moves through a planetary magnetic field, provides a new propellantless method for orbital maneuvers. This paper investigates the feasibility of using the induced Lorentz force as an auxiliary means of propulsion for spacecraft hovering. Assuming that the Earth’s magnetic field is a dipole that rotates with the Earth, a dynamical model that characterizes the relative motion of Lorentz spacecraft is derived to analyze the required open-loop control acceleration for hovering. Based on this dynamical model, we first present the hovering configurations that could achieve propellantless hovering and the corresponding required specific charge of a Lorentz spacecraft. For other configurations, optimal open-loop control laws that minimize the control energy consumption are designed. Likewise, the optimal trajectories of required specific charge and control acceleration are both presented. The effect of orbital inclination on the expenditure of control energy is also analyzed. Further, we also develop a closed-loop control approach for propellantless hovering. Numerical results prove the validity of proposed control methods for hovering and show that hovering around low-Earth orbits would be achievable if the required specific charge of a Lorentz spacecraft becomes feasible in the future. Typically, hovering radially several kilometers above a target in LEO requires specific charges on the order of 0.1 C/kg.     

Study of Solar Corona in China

Considerable progress for the study of solar corona physics has been achieved by China's space physics community. It involves the theoretical study of coronal process of solar active phenomena, solar wind origin, acceleration of solar wind and coronal mass ejections, observational and numerical study of these problems and prediction methods of solar eruptive activities (such as flares/CMEs). Here is a brief summary of the progress in this area. Main progress is put upon the following three topics: corona and solar wind, numerical method, prediction method.     

DDN状态监控系统的设计实现

设计实现了一个用于解决DDN（Digital Data Net）网络管理不足之处的新系统——DDN状态监控系统．详细论述了该系统的设寸思路和软件结构,采用了数据库、网络轮询等一系列有效的技术手段来解决DDN网络管理的不足,指出了该系统的技术创新点。     

Unscented Kalman滤波在空间飞行器被动测距中的应用

介绍了Unscented Kalman滤波及其空间飞行器被动测距中的应用。Unscented Kalman滤波通过设计少量的sigma(抽样)点,计算这些点经过非线性函数的传播,获得滤波值基于非线性方程的更新。Unscented Kalman滤波避免了广义Kalman滤波等线性化方法的缺点,并提高了滤波精度。     

浅析工学结合模式下高职生诚信教育

诚信教育是以人为本的高职教育价值观的本质要求,是高职德育工作的重要内容,也是工学结合人才培养模式的客观需要。目前高职生诚信教育存在地位认知偏差,教育方式不当和缺乏实效性和针对性等问题,本文对工学结合模式下高职生诚信教育的路径进行了初步的探讨。     

论工学结合模式下的高职院校课程开发

目前,我国高职课程设置中严重的学科体系化倾向以及对学生职业能力培养的欠缺一直都是制约高职教育教学的顽疾。推行工学结合教育模式下的高职课程设置,不仅有利于改变以往“三段式”课程模式重理论轻实践的弊端,而且对于实现职业教育“以就业为导向,以能力为本位”的最终目标也,也具有重大意义。     

高职改革发展综合实验区背景下高职体育课程的教学现状剖析

南通市是国家教育体制改革试点项目"地方政府促进高职教育改革发展综合试验区"江苏3个试点市之一。而高等职业院校体育课程是学校教育的重要分支,其教育目标既要实现高校体育基本培养目标又要实现行业、职业需求特殊目标。文章通过调查研究对南通市体育课程教学现状进行分析研究,以求找到改革的切入点与方向。     

透镜式缠绕肋压扁缠绕过程数值模拟分析

利用ABAQUS首先以各向同性材料透镜式缠绕肋的肋片压扁进行了数值模拟分析,比较了三种壳单元（S4、S4R、SC8R）和三种体单元（C3D8、C3D8R、C3D8I）模拟分析效率,并给出受力特征;进而以S4R和C3D8I进行了碳纤维复合材料肋片压扁模拟分析,并得到受力特征;最后,建立了完整的缠绕肋整体非线性有限元模型,实现了缠绕过程模拟分析,得到缠绕肋缠绕过程应力、应变及变化特征,以及缠绕弯矩。本文对缠绕肋设计及系统样机研制具有指导和参考价值。
     

GPS在气象火箭遥测跟踪上的应用

利用GPS全球定位系统、天线云台和宽波瓣天线组成的跟踪系统, 研究了接收位置信息与跟踪之间的时间差, 气象火箭理论弹道误差导致的中断跟踪,气象火箭探空仪分离后至初次定位前的跟踪, 天线云台转到359°位置后反转359°及跟踪过程中跟踪中断后的继续跟踪等关键问题,成功实现了气象火箭探空仪的遥测跟踪. 该跟踪系统在子午工程气象火箭试验中得到较好的应用, 此种跟踪方式相比传统雷达跟踪方式具有体积小、重量轻、操作简单、成本低、机动性强、跟踪可靠性强等诸多优点.      

某大型低温运载火箭无人值守加注发射技术研究

针对提升和保障航天发射人员安全问题,提出了低温运载火箭无人值守加注发射(CLVUFL)的理念和内涵.通过国内外代表性CLVUFL的技术对比,发现国内低温火箭加注发射应用CLVUFL技术存在箭地接口复杂、加注发射时间较长、关键设备可靠性有待提高、智能化自动化程度不高等主要问题.针对某大型低温运载火箭加注发射流程,通过分析...