共查询到19条相似文献,搜索用时 484 毫秒
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基于星间测距增强的卫星编队GPS相对导航研究 总被引:1,自引:0,他引:1
针对单纯差分GPS系统在精度、连续性、实时性方面存在的问题,提出了一种星间测距增强差分GPS的卫星编队组合相对导航方案。该组合相对导航系统由编队卫星中分别安装的GPS接收机、星间RF测量传感器,以及主星中运行的导航处理器组成,其中星间RF测量传感器集成了窄带通信功能,可在进行星间距离测量的同时同步进行GPS数据的互传。采用扩展Kalman滤波算法,结合简化动力学模型和GPS以及RF测量数据实现卫星编队的相对位置与速度的高精度实时递推解算。用模拟器采集数据进行了仿真验证,结果表明:在星间测距数据辅助下,星间基线长度在星间测距工作的30km范围内时,实时相对导航精度优于1mm;系统在GPS信号中断时仍可连续输出满足精度要求的相对位置、速度数据;系统初始化时间由单纯差分GPS相对导航系统的几十个历元降低到单点。 相似文献
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GPS正在改变航天器的测控格局 ,拓宽卫星和星座控制技术 ,从而构成空间编队飞行定时、测量和控制的技术基础。国内外已开发出对航天器编队飞行任务进行精确定位和导航的GPS方案。GPS将充当一大类多航天器编队飞行任务的导航系统。在当前开发的空间编队飞行技术中 ,编队航天器的测量和控制、星间链路通信、任务综合与验证、编队飞行试验台、分散式控制、高轨道航天器的相对导航等 ,无一不与GPS息息相关 相似文献
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小卫星编队飞行关键技术及发展趋势分析 总被引:2,自引:0,他引:2
卫星编队飞行是空间技术发展的一个新领域.通过编队飞行可将多颗小卫星形成一颗大的"虚拟卫星",即空间任务的预定功能由编队中各个只担当单一功能的卫星分担,由此整个卫星群可实现强大的功能.实现卫星编队飞行需要保持和控制星群的编队构型,精确确定星间的相对位置和相对速度,即相对导航.卫星编队飞行的关键技术包括轨道设计、轨道演变及控制,星间链路、编队运行管理和测控,以及卫星的自主定位、定轨.叙述小卫星编队的基本原理、轨道构成和技术特征,分析实现编队飞行所需的关键技术,介绍各国编队飞行的现有计划及未来发展趋势. 相似文献
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北斗2导航卫星星间测距与时间同步技术 总被引:3,自引:0,他引:3
针对北斗2导航卫星之间通过星间链路进行距离测量和时间同步以实现星座自主导航功能,提出了一种动态环境下基于伪码高精度距离测量和时间同步技术.它根据狭义相对论中光速不变基本原理,扩展了静态环境下双向测距和时间同步(Two-Way Ranging and Time Transmit,TWRTT)技术,使之适用于北斗2导航卫星这样的动态环境之下.理论、仿真以及工程可实现性分析表明:利用该技术,北斗2导航卫星星间测距精度可达厘米级,时间同步精度优于1ns. 相似文献
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为实现主从式卫星编队飞行中心星与环绕星的自主定轨,采用微波雷达测量卫星间相对距离、距离速率、方位角和仰角。根据动力学方程给出了导航算法,并利用扩展卡尔曼滤波(EKF)提高微波雷达相对速度的测量精度。仿真结果表明,该导航算法对主从式卫星编队较有效,且能获得较佳的导航精度。 相似文献
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基于星间链路的分布式导航自主定轨算法研究 总被引:4,自引:1,他引:3
针对脱离地面支持自主定轨的导航应用需求,提出了基于星间链路双向测距的自主导航定轨算法。文章分析了导航星座星间链路双向伪距测量模型,给出了分布式自主定轨数据流程,设计了导航星座基于星间链路分布式自主定轨算法。根据国际卫星导航服务组织公开的真实GPS系统事后精密星历,对本文设计的自主定轨算法进行仿真验证,结果表明:采用该设计的自主导航算法在自主定轨90天末期,用户测距误差(URE)达到30 m左右,验证了该设计的自主定轨算法具有较高的自主定轨精度。 相似文献
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导航星座自主导航的时间同步技术 总被引:5,自引:4,他引:5
导航星座自主导航能够有效地减少地面测控站的布设数量,减少地面站至卫星的信息注入次数,降低系统维持费用,实时监测导航信息的完好性,增强系统的生存能力。卫星时间同步是实现导航星座自主导航的关键技术之一,而星载原子时钟的频率稳定性能直接影响着卫星时间同步精度。本文基于星载原子时钟频率稳定性的Allan方差表达,建立系统状态方程,并以星间双向测量伪距差作为基本观测量,组成系统测量方程。从而,可以设计适用于导航星座卫星时间同步的Kalman滤波算法。系统仿真结果表明:通过滤波处理星间双向测距数据,不断地更新卫星时钟参数,能够实现星座卫星自主高精度时间同步。 相似文献
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航天器编队飞行及其关键技术的开发 总被引:1,自引:0,他引:1
简要论述由分布式航天器系统构成的空间编队飞行的概念 ,扼要介绍 NASA为未来航天器编队飞行项目开发的几项关键技术 ,着重阐明基于 GPS的分散式编队飞行控制和相对导航技术能充当未来多星编队飞行任务的导航系统 ,从而使未来的空间科学研究发生深刻变化 相似文献
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This paper presents a systems approach to optimization of the size and orbital life of photovoltaic systems via minimizing the nighttime energy demand while maximizing the daytime energy consumption. The Day-Night Management of Load (DANMOE) strategy calls for sizing the system to a pre-selected day/night average load power ratio and operating the spacecraft in orbit within the day and night capacity capability, rather than the conventional single orbital average power capability. Examples for the Space Station and the telecommunication satellites show that the reduction in their specific masses can be substantial using any of the photovoltaic system technologies. The DANMOE scheme may also be used effectively to extend the life of batteries on currently orbiting satellites, and hence prolong their lifetime. The paper also discusses other benefits at the spacecraft level and the method of implementing the DANMOE approach. 相似文献
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在比较分析编队卫星相对定位与陆地相对定位技术的基础上,结合陆地相对定位技术和 卫星精密定轨技术提出了基于GPS进行编队卫星相对定位的方法及原理。文章采用2004年4月 1日到10日的GRACE卫星实测数据进行了相对定位计算,并采用KBR观测数据对本文相对定位 结果和JPL单独定轨结果进行了外部检核,检核结果表明:1. 与直接采用单独定轨结果相 比,该方法可以明显提高卫星的相对位置精度。2. 利用本文方法计算的两颗GRACE卫星相 对位置精度约为4.5 mm。
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The PRISMA in-orbit test bed will demonstrate guidance, navigation, and control strategies for spacecraft formation flying and rendezvous. The project is funded by the Swedish National Space Board and the prime contractor is the Swedish Space Corporation. The project is further supported by the German Aerospace Center, the Technical University of Denmark, and the French Space Agency. PRISMA was launched on June 15, 2010 and after three weeks of operations, all on-board systems and units have passed an initial commissioning phase. Separation of the two PRISMA satellites from each other is expected by mid-August 2010.PRISMA consists of two spacecraft: MAIN and TARGET. The MAIN spacecraft has full orbit control capability while TARGET is attitude controlled only.The Swedish Space Corporation is responsible for three groups of guidance, navigation, and control experiments. These experiments include GPS- and vision-based formation flying during which the spacecraft will fly in passive as well as forced motion. The three experiments are: autonomous formation flying, proximity operations with final approach/recede maneuvers, and autonomous rendezvous. This paper presents system test results from two of these experiments as obtained with the flight-ready system. The system tests consist of a series of simulations performed on the flight model spacecraft with a large amount of hardware in the loop. 相似文献
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我国天基综合信息网构想 总被引:4,自引:2,他引:2
阐述了天基综合信息网的定义、组成和特征;介绍了美国和欧洲天基综合信息网的研究情况;提出了我国天基综合信息网的体系架构,其中包含通信卫星、导航卫星、遥感卫星、载人飞船等航天器和临近空间各种飞行器,以及地面系统。分析了该网络的特点和可用的网络协议结构;探讨了该网络的组网结构、网络协议、服务质量(QoS)路由、网络管理、网络安全防护、激光通信和星载处理交换等多项关键技术。依据国情,提出了我国天基综合信息网构想。此构想采用双层(地球静止轨道和低地球轨道)通信卫星星座和导航卫星星座,实现全球全时覆盖空间层航天器、临近空间层飞行器和地面层各种用户终端,通过星间链路、星地链路和地面线路组成一个空天地一体化的全球信息网络。在国外不设地球站的情况下,该网络可实现:国内测控站测控我国全球运行的卫星;国内遥感站实时接收我国全球遥感卫星发送的信息;国内关口站管理我国授权的全球用户站之间的互通信息。最后,提出了开展我国天基综合信息网的可行性研究建议。 相似文献
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The PRISMA project for autonomous formation flying and rendezvous has passed its critical design review in February–March 2007. The project comprises two satellites which are an in-orbit testbed for Guidance, Navigation and Control (GNC) algorithms and sensors for advanced formation flying and rendezvous. Several experiments involving GNC algorithms, sensors and thrusters will be performed during a 10 month mission with launch planned for the second half of 2009.The project is run by the Swedish Space Corporation (SSC) in close cooperation with the German Aerospace Center (DLR), the French Space Agency (CNES) and the Technical University of Denmark (DTU). Additionally, the project also will demonstrate flight worthiness of two novel motor technologies: one that uses environmentally clean and non-hazardous propellant, and one that consists of a microthruster system based on MEMS technology.The project will demonstrate autonomous formation flying and rendezvous based on several sensors—GPS, RF-based and vision based—with different objectives and in different combinations. The GPS-based onboard navigation system, contributed by DLR, offers relative orbit information in real-time in decimetre range. The RF-based navigation instrument intended for DARWIN, under CNES development, will be tested for the first time on PRISMA, both for instrument performance, but also in closed loop as main sensor for formation flying. Several rendezvous and proximity manoeuvre experiments will be demonstrated using only vision based sensor information coming from the modified star camera provided by DTU. Semi-autonomous operations ranging from 200 km to 1 m separation between the satellites will be demonstrated.With the project now in the verification phase particular attention is given to the specific formation flying and rendezvous functionality on instrument, GNC-software and system level. 相似文献
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The functionality of a distributed system can be significantly enhanced by exploring non-traditional approaches that leverage on inherent aspects of distributed systems in space. Till now, the benefit of distributed systems in space has been limited to enhancing coverage, multipoint sensing, creating virtual baselines (e.g. interferometry) or to enhance redundancy. The list of benefits can be further expanded by understanding the nature of distributed systems and by productively incorporating it into mission and spacecraft design. For example, prior knowledge of the spatial evolution of such systems can lead to innovative communication architectures for these distributed systems. In this paper, different communication scenarios are investigated that can enhance the communication link between the distributed system and ground.The increasing trend towards highly miniaturized spacecraft (nano- to femto-satellites) and proposals to launch hundreds or even thousands of them in massively distributed space missions have expanded the interest in distributed systems with miniature spacecraft. It is important to understand how and which, functionalities and systems, scale with size and number. Scalable systems are defined and addressed at a basic level and the utility of scaling rules and trends in identifying optimal configurations of distributed systems is explored.In this paper we focus on the communication capability and identify methods to enhance the communication link between a distributed space segment, consisting of a number of simplistic, resource limited femto-satellites, and earth. As an example, the concept of forming a dynamic phased array in space with the elements of a distributed space system in low-earth orbit is investigated. At the ground receiver, the signals from different satellites forming the array should not differ in phase by more than one-third the transmission wavelength, to ensure constructive superposition. Realizing such a phased array places strict accuracy requirements on time synchronization and knowledge of relative separation between the satellites with respect to the ground receiver. These constraints are derived and discussed. 相似文献