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Applications of two-way satellite time and frequency transfer in the BeiDou navigation satellite system 被引量:7
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作者 ShanShi Zhou xiaogong hu +7 位作者 Li Liu Rui Guo LingFeng Zhu ZhiQiao Chang ChengPan Tang XiuQiang Gong Ran Li Yang Yu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第10期72-80,共9页
A two-way satellite time and frequency transfer(TWSTFT) device equipped in the BeiDou navigation satellite system(BDS)can calculate clock error between satellite and ground master clock. TWSTFT is a real-time method w... A two-way satellite time and frequency transfer(TWSTFT) device equipped in the BeiDou navigation satellite system(BDS)can calculate clock error between satellite and ground master clock. TWSTFT is a real-time method with high accuracy because most system errors such as orbital error, station position error, and tropospheric and ionospheric delay error can be eliminated by calculating the two-way pseudorange difference. Another method, the multi-satellite precision orbit determination(MPOD)method, can be applied to estimate satellite clock errors. By comparison with MPOD clock estimations, this paper discusses the applications of the BDS TWSTFT clock observations in satellite clock measurement, satellite clock prediction, navigation system time monitor, and satellite clock performance assessment in orbit. The results show that with TWSTFT clock observations, the accuracy of satellite clock prediction is higher than MPOD. Five continuous weeks of comparisons with three international GNSS Service(IGS) analysis centers(ACs) show that the reference time difference between BeiDou time(BDT) and golbal positoning system(GPS) time(GPST) realized IGS ACs is in the tens of nanoseconds. Applying the TWSTFT clock error observations may obtain more accurate satellite clock performance evaluation in the 104 s interval because the accuracy of the MPOD clock estimation is not sufficiently high. By comparing the BDS and GPS satellite clock performance, we found that the BDS clock stability at the 103 s interval is approximately 10.12, which is similar to the GPS IIR. 展开更多
关键词 BDS TWSTFT satellite clock prediction accuracy system reference time Allan variance
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LEO-LEO掩星大气反演技术及误差分析 被引量:1
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作者 付乃锋 郭鹏 +1 位作者 仵梦捷 胡小工 《遥感科学(中英文版)》 2016年第2期51-64,共14页
本文介绍了LEO-LEO掩星大气反演算法的物理机制,基本流程及计算原理,同时模拟仿真分析了多种误差源(例如钟误差、多路径效应以及LEO卫星轨道误差等)对反演结果的影响。通过统计反演温度及湿度发现:现有的卫星钟的稳定度及LEO卫星定轨精... 本文介绍了LEO-LEO掩星大气反演算法的物理机制,基本流程及计算原理,同时模拟仿真分析了多种误差源(例如钟误差、多路径效应以及LEO卫星轨道误差等)对反演结果的影响。通过统计反演温度及湿度发现:现有的卫星钟的稳定度及LEO卫星定轨精度满足反演需求;对于多路径效应,需要抑制强振幅、低频噪音。为LEO-LEO掩星观测、数据预处理以及数据反演流程优化提供了重要的解决思路与技术。 展开更多
关键词 LEO-LEO无线电掩星 中性大气层 平台和测量误差 EGOPS
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发动机惰轮铁轮开裂失效分析
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作者 曹鑫 陈小工 胡四军 《理化检验(物理分册)》 CAS 2017年第9期659-663,共5页
某汽车发动机在行驶过程中出现助力转向系统失效的现象,拆解后发现发动机的惰轮发生了开裂失效。通过断口分析、化学成分分析、硬度测试、金相检验、受力分析等方法,分析了该惰轮失效的原因。结果表明:惰轮铁轮本身实际承受的力大于惰... 某汽车发动机在行驶过程中出现助力转向系统失效的现象,拆解后发现发动机的惰轮发生了开裂失效。通过断口分析、化学成分分析、硬度测试、金相检验、受力分析等方法,分析了该惰轮失效的原因。结果表明:惰轮铁轮本身实际承受的力大于惰轮的设计最大径向力,铁轮的设计强度不足,从而导致铁轮在使用过程中沿圆弧倒角发生低周疲劳开裂失效。最后通过改进惰轮的设计工艺,有效地解决了该问题。 展开更多
关键词 惰轮 铁轮 开裂 低周疲劳 受力分析
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