共查询到20条相似文献，搜索用时 441 毫秒
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Linux正大步进入实时控制领域,但是Linux并没有提供对周期性实时任务的直接支持.如何在Linux下进行周期性实时任务的开发是一个难题.分析了周期性实时任务的开发内容,从实时任务的特性设置、任务的周期实现到任务的具体功能实现,并给出了关键代码. 相似文献
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在组合PPP函数模型分析的基础上，采用CNES提供的多系统实时轨道和钟差信息，实现GPS/Galileo组合单双频实时静动态PPP，并选取10个MGEX站10 d的观测数据进行解算分析。结果表明，单双频实时静态PPP中，GPS/Galileo组合的定位精度略优于单纯的GPS；单双频实时动态PPP中，GPS/Galileo组合具有较好的定位效果。相较于单纯的GPS，GPS/Galileo组合单频PPP在E、N、U方向平均精度为10.6 cm、9.8 cm、22.5 cm，分别提高了5.4%、4.9%、10.4%；双频PPP在E、N、U方向平均精度为4.3 cm、2.9 cm、7.0 cm，分别提高了6.5%、6.5%、5.4%。同时，GPS/Galileo组合PPP较GPS在收敛时间方面也有一定的改善。 相似文献
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近年来,Linux在嵌入式方面的应用越来越广泛,改进Linux的性能,使其适用于实时领域成为一个极具潜力的发展方向。影响Linux实时性的主要因素之一是Linux内核的不可抢占性,因此对内核抢占性的研究迫在眉睫,对其进行分析和研究,详细阐述了抢占锁、互斥锁、中断处理、调度函数的实现原理并提出改进方案,最后测试修改后的内核并与原内核的数据进行了分析和比较。 相似文献
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Linux 实时性能瓶颈分析 总被引：1，自引：0，他引：1
从调度机制、信号量和消息队列3方面将Linux、RT-Linux和VxWorks进行了综合对比，并结合测试用例得出了影响Linux实时性能的瓶颈。最后从上述3方而给出了Linux实时性能改造的可行性办法。 相似文献
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针对IGS RTS（real time service）实时数据流产品难以避免的数据中断现象,开展了RTS数据中断修复方法研究,提出“插值修复”方法。在对RTS数据中断的区间分布进行统计分析的基础上,选取15 min为可修复的最大数据中断区间;采用常用的拉格朗日插值方法进行RTS轨道数据中断修复,对不同阶数的插值修复效果进行比较;提出新的基于RTS改正的精密卫星钟差计算方法,采用拉格朗日插值、三次样条插值、线性插值和线性拟合等方法进行RTS钟差数据中断修复和结果对比;最后利用IGS跟踪站观测数据和修复后的RTS产品,进行静态模拟动态的准实时PPP实验,对“插值修复”方法的效果和PPP定位精度进行验证。 相似文献
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EDF调度算法具备高CPU利用率、可调度较大的任务集的优点.将EDF调度算法和静态优先级调度算法的可控性相结合,提出了一种新的调度算法--SEDF调度算法(Strong Earliest Deadline First).首先从理论上分析了SEDF算法的可调度性条件及其时间特性,并针对SEDF调度算法对Linux系统环境提出了一些修改;然后通过实验数据对比了EDF算法和SEDF算法,证明SEDF算法具备更强的控制能力,更利于高优先级任务的优先运行,更能够实现Linux内核对实时任务更高的响应能力. 相似文献
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实验模拟服务器端不同更新频率的SSR改正数对实时精密单点定位的影响，以及客户端改正数中断时长对实时精密单点定位的影响。结果表明，服务器端SSR改正数的播发频率控制在30 s以内可获得cm级定位精度；客户端的SSR改正数中断在150 s之内可获得cm级定位精度，改正数中断200 s可获得20 cm的定位精度，改正数中断300 s可获得亚m级定位精度。 相似文献
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在星载单频GPS实时定轨中引入NeQuick2三维电离层延迟改正模型，首先利用GIM对Klobuchar和NeQuick2模型进行精度评估，然后使用不同电离层改正方法模拟仿真星载单频GPS实时定轨实验。结果表明，当卫星轨道低于500 km时，相比于传统的改进Klobuchar改正的定轨精度，利用NeQuick2改正的定轨精度提高0.2 m左右，与双频伪距法定轨精度相当。 相似文献
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针对目前常用的GPS实时钟差确定算法主要基于实时观测数据流实现,使产品可靠性和完整性受限于网络质量,及广播星历和IGU-P精度较低的问题,提出并实现基于小时观测文件拼接的实时钟差确定算法。该算法基于小时观测文件数据,通过将钟差估计与自适应超短期钟差预报相结合以确定实时钟差。30 d实时在线结果显示,基于小时观测文件确定的实时钟差精度约为0.25 ns,优于广播星历和IGU-P,与IGS RTS提供的实时钟差精度相当,且能保证产品的可靠性和完整性。 相似文献
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Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area. 相似文献
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Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter. 相似文献
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《极地研究(英文版)》2014,(3)
正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied 相似文献
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《山地科学学报》2014,(4):I0004-I0009
<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet. 相似文献
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《山地科学学报》2014,(4)
<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by 相似文献
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References： 《极地研究(英文版)》2007,18(1):73-83
Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated. 相似文献
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《中国海洋大学学报(英文版)》2014,(3):I0001-I0001
<正>The Journal of Ocean University of China(Oceanic and Coastal Sea Research)is a comprehensive academic quarterly sponsored by the Ocean University of China,published one volume per year.This journal is devoted to the publication of the theoretical and applied research 相似文献