Relative navigation for multi-spacecraft system with GPS

A type of multi-spacecraft system with kinematical restraint but no structural restraint and force action is considered. Both the absolute and relative navigation information is required for this multi-spacecraft system, but the relative information is more critical and the accuracy requirements for relative information will be much higher than those for the absolute information. In this paper, the Global Positioning System (GPS)/Differential GPS (DGPS) are introduced and used for relative navigation. Relative motion of space vehicles is modeled. Relative position, relative velocity and relative attitude are represented and solved by GPS/DGPS measurements. Using a type of commercial GPS receiver onboard spacecraft and relative differential GPS technique, the relative navigation of space vehicles can be implemented in real-time     

Achieving higher levels of electronic integration throughsystem-on-chip

All aerospace vehicles have the common constraint of limited space for the electronic systems. The challenge has always been how to pack effective electronic systems into the space available. Higher levels of electronic integration can give a competitive advantage; for example, by providing extra channels in a communications satellite thereby increasing revenue to the operator. Today's deep sub-micron manufacturing processes for integrated electronics offer an opportunity for a step change for electronic functionality that can be packaged in a given space. This technology makes possible, for the first time, a true system-on-chip approach to electronic systems, which is already being exploited by the commercial sector in products such as the mobile telephone     

Future trends in space photovoltaics

The Air Force, NASA, NRL and the commercial sector are all using small spacecraft to a greater extent in order to provide more cost-effective access to space. This paper discusses the generic photovoltaic technologies which are being studied and/or developed to support these smaller spacecraft, and identifies several specific examples. The unique requirements of these mission types include lower power arrays, arrays with lower mass and stowed volume which will be more compatible with small launch vehicles, and power systems with lower fabrication costs     

临近空间高超声速飞行器防热材料的发展

简要叙述了临近空间的定义及临近空间的飞行器类型,回顾了美国临近空间高超声速飞行器的发展历程,主要介绍猎鹰计划的研究目标及军事应用,重点介绍猎鹰计划中高超声速飞行器防热材料的发展.     

航天器轨迹优化的通用数值方法

给出了航天器轨迹优化的一种通用数值仿真方法，该方法是由静态参数优化和动态参数优化构成，其中，静态参数优化采用可变误差多面体算法，动态参数优化采用基于最优控制理论的共轭梯度方法。     

临近空间飞行器推进系统预冷器关键技术

临近空间由于其在现代战争中的重要战略意义已成为各国航空航天领域的研究重点,高超声速飞行器更是国家临近空间军事实力的一个重要标志。由于吸气式高超声速飞行器具有较高的飞行高度与马赫数,预冷技术已成为高超声速飞行器推进系统中的一项关键技术,而高性能预冷器设计是预冷技术的一个重要研究方向,预冷器的可靠性与流动传热特性是预冷系统的重要影响参数,对于紧凑、高效、高可靠性先进预冷器的研究具有十分重要的意义。基于目前公开的临近空间高超声速飞行器的主要动力形式及其对预冷技术的刚性需求,对预冷器设计中的关键技术与发展方向做了详细的阐述。     

高超声速临近空间飞行器非开普勒轨道研究

以高超声速临近空间飞行器非开普勒轨道弹跳飞行为研究对象,论证了高超声速临近空间飞行器飞行轨道属于非开普勒轨道的研究范畴.首先给出了非开普勒轨道机动巡航段、再人段和再入瞬间的动力学方程;其次研究了再入瞬间高超声速临近空间飞行器的位置矢量求解问题,提出弹跳系数的概念;最后进行了仿真分析.仿真结果表明,非开普勒轨道动力学方程...     

先进空间运输系统气动设计综述

天地往返运输系统是能够自由进出空间轨道、安全返回地球表面、执行天地往返运输任务的航天运输体系。近年来,随着先进动力、新材料、新工艺的带动效应逐渐显现,各航天集团开始了新一轮先进天地往返系统的研究,其中大量研究项目针对具备完全可重复使用、可大幅降低运送有效载荷进入太空成本的先进天地往返运输系统展开。本文针对这一热点领域进行综述性研究,对不同类型进出大气层飞行器的气动设计特点进行了分析,结果表明跨大气层飞行器是天地往返运输系统的主要载体,认为未来主要以火箭助推入轨滑翔再入和水平起飞水平返回为主要发展方向,两类飞行在气动设计方面有高超飞行器宽域飞行适应性的共性难题,同时在气动-动力一体化化设计方面又有较大的差异。     

临近空间高超声速飞行器天文导航系统综述

临近空间是航天与航空业务领域的结合部，具有重要的战略价值。高超声速飞行器是临近空间力量部署的重要载体，已逐渐进入应用部署阶段。临近空间高超声速飞行器的飞行环境和任务条件对导航系统提出了新的更高要求。在总结临近空间高超声速飞行器的导航技术研究进展的基础上，对天文导航技术的应用环境和条件进行了系统的分析和探讨，提出了5个重点研究方向，包括：星图采集效能、光学误差模型、视场观测机理、姿态更新速率、小型化模块化工程化等。研究结果可为临近空间高超声速飞行器天文导航系统的设计提供参考。     

Navigation error analysis for the rocketplane XP

bd Systems has supported the navigation architecture development of the Rocketplane XP as part of its responsibility as the vehicle guidance, navigation, and control (GN&C) subsystem lead contractor. The Rocketplane XP is a reusable sub-orbital space-plane being designed by Rocketplane Limited, Inc. for the commercial space tourism market. The horizontal take-off/horizontal landing vehicle, which will be one of the world's first true manned aerospace vehicles, has a short development schedule and began operation in 2007. bd Systems performed a detailed trade study to select the navigation subsystem and developed high-fidelity error models for use in the overall vehicle six-degree-offreedom (6DOF) simulation in order to determine the effects of navigation errors on vehicle performance.     

对我国商业航天测控管理有关问题的初步探讨

国际商业航天的蓬勃发展带动了国内商业航天的兴起。以实现商业卫星高效便捷管理为目的,调研了国内外商业航天与商业航天测控的发展现状,分析了国外商业航天以及商业航天测控发展对我国商业航天测控管理的有关启示,得出了测控管理多元化大势所趋、适度鼓励商业航天测控发展势在必行等结论。同时,对我国商业航天测控管理中加强航天立法、探索商业航天测控管理新模式、加强商业卫星管理服务等问题进行了初步探讨,建议从国家层面、行业规范层面制定航天法规,卫星任务中心应支持对外联网,并加强商业航天测控地面站的国际合作,从而提高商业卫星频率、轨位、空间目标编目、发射与回收等管理服务能力。     

高速再入飞行试验再入条件优化设计

飞行器返回再入时将经历极高的气动热环境,因此深空探测返回飞行器,尤其是载人飞船需要通过实际飞行试验验证相关性能,为降低成本和研制风险,通常采用大再入角和相对第二宇宙速度较低的再入速度进行飞行试验。为获得能实现高热流密度验证的最小能量再入任务方案,采用优化设计手段对飞行试验的再入角和速度以及倾侧角控制进行设计,经仿真分析表明,优化结果可达到飞行试验要求的热流密度,并可将再入速度需求降低约2．1 km／s。     

Enhanced space integrated GPS/INS (SIGI)

Safe, reliable, and low cost space-based navigation is being provided with embedded INS/GPS systems such as the space integrated GPS/INS (SIGI). The SIGI is being used for various space vehicle applications such as launch vehicles, orbital vehicles, and re-entry vehicles. This paper describes current space vehicle navigation capabilities. The SIGI is being enhanced to provide additions to these existing capabilities with such items as higher processing and a commercial-off-the-shelf operating system. This will allow hosting of various software applications such as advanced navigation functions, flight control, guidance and vehicle management algorithms. The SIGI can host redundancy management functions by incorporating a cross channel data link card (CCDL) using a high speed firewire bus. The SIGI can then be used as a redundancy management platform which has application to current space vehicle avionics topologies incorporating distributed processing architectures     

基于航行力学思想的坐标系研究

针对理论分析及工程实践对传统研究武器系统在多种介质环境中运动的学科提出的要求,提出了建立"航行力学"的构想。首先提出了航行与航行器的概念;其次将航行器在水中、大气中、外太空等不同介质环境下的坐标系及空间位置与姿态进行了定义;最后,讨论了航行器各坐标系的相互关系及转换,为初步建立航行力学理论奠定了基础。     

Advanced materials for next generation NiMH portable, HEV and EVbatteries

While Ovonic NiMH batteries are already in high volume commercial production for portable applications, advances in materials technology have enabled performance improvements in specific energy (100 Wh/kg), specific power (600-1000 W/kg), high temperature operation, charge retention, and voltage stability. Concurrent with technology advances, Ovonic NiMH batteries have established performance and commercial milestones in electric vehicles, hybrid electric vehicles, as well as scooter, motorcycle and bicycle applications. As important as these advances, significant manufacturing cost reductions have also occurred which allow continued growth of NiMH technology. In this paper, advances in performance, applications and cost reduction are discussed with particular emphasis on the improved proprietary metal hydride and nickel hydroxide materials that make such advances possible     

状态预测神经网络控制应用于小型可回收火箭

随着商业航天的到来，可重复使用运载器的研究受到广泛关注，以SpaceX为代表的商业航天公司研发的部分可回收火箭表现出了前所未有的竞争力。为了研发可回收火箭技术，翎客航天利用民间工业力量研制了RLV-T3小型可回收火箭验证机，并在该验证机上通过数百次试验逐渐掌握了垂直起降（VTVL）技术。主要介绍了翎客航天在VTVL技术中的一项动力控制技术，提出了状态预测神经网络控制（SPNNC）算法。该算法具有鲁棒性强、适用范围广、控制参数易调整等优点。详细地描述了该算法的原理，并通过Simulink对SISO和MIMO 2种系统进行了仿真。同时详细地论述了将状态预测神经网络控制算法应用于RLV-T3小型可回收火箭的飞行及回收的试验，包括RLV-T3小型可回收火箭的基本特点、控制难点、存在的问题，飞行过程中各物理量的曲线和试验结论。经试验验证，状态预测神经网络控制算法具有良好的控制性能，基于该控制技术，即状态预测神经网络控制算法的RLV-T3小型可回收火箭验证机可以安全地实现垂直起飞、弹道飞行、空中悬停、软着陆回收全流程。     

Impact of erosion testing aspects on current and future flight conditions

High speed of aero vehicles including commercial and military aircraft, missiles, unmanned air vehicles, as well as conceptual aircraft of the future are imposing larger restrictions on the materials of these vehicles and highlight the importance of adequate quantification of material behavior and performance during different flight conditions. Erosion due to weather conditions and other present particles such as hydrometeors; rain, hail and ice, as well as sand, volcanic ash and dust resulting from residues in the atmosphere are eminent as hazardous on the structure of a flying vehicle and may adversely influence the lifecycle of the structure. This study outlines an extensive review of research efforts on erosion in aviation and provides a basis for comparison between different apparatus simulating rain erosion and their usage within the aerospace industry. The significant aspects of erosion testing and future prospects for erosion impact are further addressed for forthcoming generations of flying vehicles.     

Automatic CCTV surveillance-towards the VIRTUAL GUARD

The VIRTUAL GUARD is a general-purpose computer-based CCTV surveillance system for detecting potential criminal activity in public areas. The system monitors all activity in the surveillance area, the vast majority of which is people innocently going about their normal business. It will alarm when the observed activities of particular pedestrians and vehicles match any of the pre-defined “suspicious behaviour criteria” programmed into the system. At the same time as analysing movement behaviour, the system uses computer-controlled pan tilt zoom cameras to obtain close-up video recordings of any pedestrians and vehicles at the scene. The system can provide automatic surveillance in many different situations, from parking areas and commercial districts, to housing, recreational and transport facilities. It is particularly suited to the protection of government or commercial buildings located on city streets or other public areas where it is not possible to install perimeter fences     

光纤陀螺在宇航领域中的应用及发展趋势

光纤陀螺作为全固态惯性仪表,具有长寿命、高可靠和空间环境适应性好等显著优点,已广泛应用于国外各类宇航飞行器上。我国光纤陀螺的宇航应用起步于21世纪初,现已应用于导航卫星、通信卫星、遥感卫星、载人飞船、月球探测器等多种宇航飞行器上,对我国宇航飞行器性能的快速提升起到了重要的促进作用。主要介绍了国内外光纤陀螺宇航应用的情况,重点说明了目前几种主流光纤陀螺的技术方案,并对几种新型光纤陀螺(如光子晶体光纤陀螺)的宇航应用特点进行了分析。最后,从宇航应用的技术需求出发,指出了光纤陀螺宇航应用的几类关键技术和发展趋势。     

Vehicle health management research for legacy and futureoperational environments

The Air Force will require the ability to diagnose and predict component failures in order to more effectively meet the requirements of the fast and agile Aerospace Expeditionary Force (AEF) and future space vehicles. This paper will cover topics relevant to vehicle health management for current and anticipated support environments. It reflects current projects underway at the Air Force Research Laboratory in the air vehicles and human effectiveness directorates. Specifically, the predictive failures and advanced diagnostics (PFAD) for legacy aircraft, passive aircraft status system (PASS), and the space operations vehicle integrated system (SOVIS) projects will be discussed