共查询到20条相似文献,搜索用时 15 毫秒
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Wong [1] recommends that 16 additional LORAN-C ground stations are needed to provide redundant coverage throughout the conterminous U.S. so that LORAN-C can provide the primary navigation service to civil aviation. The purpose of this paper is to estimate the effect of the interference from the additional stations on the acquisition (phase code identification and third cycle selection) and track modes of a LORAN-C receiver whose detection process is based on the sequential decision theory. This receiver model represents a modern design using microprocessor technology. The results are compared against the requirement that acquisition be completed 90 percent of the time within 7.5 minutes. The impact of cross-rate interference (CRI) on the track mode is estimated using a time-domain analysis. 相似文献
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The Coast Guard is extending the Continental United States (CONUS) LORAN-C coverage as part of the Federal Aviation Administration project to incorporate LORAN-C into the National Airspace System. The increased coverage will expand the number of airports approved for LORAN-C non-precision instrument approaches and enable direct Instrumental Flight Rules (IFR) routing by suitably equipped aircraft in and through the mid-continent region of the United States. The project will involve construction of a new LORAN-C chain which will be linked to the existing CONUS chains. In addition to the aviation benefits, the Mid-Continent LORAN-C Expansion will broaden the availability of LORAN-C positioning to a growing number of terrestrial users such as resource management, emergency response and fleet management. 相似文献
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GNSS用户端自主完好性监测研究综述 总被引:5,自引:1,他引:4
随着全球卫星导航系统的快速发展,对航空安全提出了挑战,完好性监测问题愈发凸显,用户端自主完好性监测(RAIM)是研究的重点之一。针对RAIM问题,首先介绍了所需导航性能的4个重要参数:精度、完好性、可用性和连续性。从单卫星故障下的RAIM、多卫星故障下的RAIM、高斯噪声下的RAIM 3个方面,综述了国内外相关的重要研究,主要涉及了3个层次内容:算法、计算保护限值和可用性,并指出了目前研究存在的不足。其次介绍了近期研究的新趋势与取得的成果。最后,展望了未来的研究方向。 相似文献
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Navigation message designing with high accuracy guarantee is the key to efficient navigation message distribution in the global navigation satellite system(GNSS). Developing high accuracy-aware navigation message designing algorithms is an important topic. This paper investigates the high-accuracy navigation message designing problem with the message structure unchanged.The contributions made in this paper include a heuristic that employs the concept of the estimated range deviation(ERD) to improve the existing well-known navigation message on L1 frequency(NAV) of global positioning system(GPS) for good accuracy service; a numerical analysis approximation method(NAAM) to evaluate the range error due to truncation(RET) of different navigation messages; and a basic positioning parameters designing algorithm in the limited space allocation. Based on the predicted ultra-rapid data from the ultra-rapid data from the international GPS service for geodynamic(IGU), ERDs are generated in real time for error correction.Simulations show that the algorithms developed in this paper are general and flexible, and thus are applicable to NAV improvement and other navigation message designs. 相似文献
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目前机电作动器由于具有干净、维护方便等优点,越来越受到航空业的青睐。航空机电作动器的特点是控制精度、稳定性和响应速度要求高,针对以上特点,提出了一种基于多层神经网络的快速终端滑模控制策略。为了提高航空作动器响应速度和跟踪精度,设计了快速终端滑模控制策略,不仅可以加快系统响应而且可以在无扰动情况下实现系统的有限时间稳定。针对系统参数不确定性和外部扰动,设计多层神经网络进行估计并通过前馈方法加以补偿。针对神经网络的重构误差,设计了非线性鲁棒项加以克服。利用李亚普洛夫稳定性定理证明了控制系统在有扰动情况下可以实现有界稳定。实验结果表明:所设计的控制器具有良好的参数自适应和抗干扰能力,同时具有更高的跟踪精度和更快的响应速度。 相似文献
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分析了国内外通用飞机机载数据记录仪的现状,指出我国现有通用飞机机载数据记录仪所存在的不足之处.同时,根据未来通用飞机的发展,深入研究了新型通用飞机机载数据记录仪的功能、特点需求,并且基于模块化思想,提出了新型通用飞机机载数据记录仪的设计思路,给出了新型通用飞机机载数据记录仪的软硬件体系结构,并对其核心模块的功能进行了详细的阐述.最后,简述了新型通用飞机机载数据记录仪的应用. 相似文献
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航空电子系统的发展趋势 总被引:1,自引:0,他引:1
牛强军 《西安航空技术高等专科学校学报》2011,29(1):13-17
在分析作战飞机效能、作战能力指数、航空电子系统功能的基础上,介绍联合式航电系统、综合航电系统、先进的综合航电系统的现状,根据各国进行的电子战、传感器、数据链、导航和通信系统的研究现状和计划,分析未来航空电子系统发展的特点、特征、技术措施和趋势。 相似文献
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The Federal Radionavigation Plan states that all present navigation and landing guidance facilities will be retired starting in 2005, and full dependence for these functions will be placed on augmented GPS. Once this is implemented, civil aviation will be totally vulnerable to terrorist jamming of the GPS signals over wide earth areas with widespread disruption of air traffic and potential disasters. It has become apparent that the use of GPS/GNSS is complex and expensive for the required civil aviation functions. It is clear that a different system form is needed for civil aviation, a redundant satellite/ground based system that will prevent it from being a jamming target while providing ATC surveillance, area navigation, collision warning/avoidance, high-speed data link and Category I landing guidance globally, plus precision Category III guidance in the terminal areas as needed. Such a system will be described 相似文献
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Omega is a navigation radio aid having worldwide coverage with good accuracy. By choosing among the phase-difference lines of position, much as with celestial navigation, high and uniform accuracy can be maintained. Omega is introduced by discussing its qualities. Geometry, propagation, lane identification, synchronization, secondary modes of operation, accuracy, receivers, and transmitter stations are covered 相似文献
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随着航空技术的突破性进展,国际民航组织提出了基于性能的通信导~(CNS)系统,其由所需通信性能(RCP)、所需导航性能(RNP)和所需监视性能(RSP)组成。同时,缩小间隔标准可以有效地缓解流量增长和减少延误.因此基于CNS性能的垂直间隔碰撞风险评估具有重要意义。建立了CNS性能条件下的定位误差模型,推导出了垂直重叠率和侧向重叠概率的计算公式,应用于Reich碰撞风险模型。通过算例对垂直间隔碰撞风险进行了安全评估计算,结果表明所给出的基于CNS性能的垂直间隔碰撞风险评估模型是可行的。 相似文献
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Omega is a navigation radio aid having worldwide coverage with good accuracy. By choosing among the phase-difference lines of position?much as with celestial navigation?high and uniform accuracy can be maintained. Developed and tested by USNEL and USNRL, Omega is introduced by a discussion of qualities not shared by Gee. Decca, or Loran. 相似文献
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时分数据调制(TDDM)裂谱信号作为一种新调制信号,具有独有的电文翻转位模糊特性,导致了采用通常的搜索方法无法正确输出电文的现象。针对TDDM裂谱信号特性以及现有搜索方法的不足,提出了一种解模糊位搜索法。该方法主要分为合路快捕及解模糊位判决两个阶段。其合路快捕阶段,不但可以快速缩小搜索范围,而且可以避免由扩频方式而引起的漏捕现象;解模糊位判决阶段,可以去除电文翻转位的模糊度,正确输出电文的翻转位置。在理论推导的基础上,从性能及信噪比容限角度进行了仿真测试,测试结果表明,解模糊位搜索法对TDDM裂谱信号的电文翻转位判决精度可以达到100%。 相似文献
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伪距解除相关法在GPS/SINS紧组合系统中的应用研究 总被引:3,自引:0,他引:3
介绍了伪距解除相关法的原理 ,设计了一种加权平均跟踪误差估计器 ,用以估计 GPS接收机码环跟踪误差。研究结果表明 ,与未对伪距测量值进行修正时相比 ,应用伪距解除相关技术可以减小组合系统的导航误差 ,提高系统的导航精度 相似文献