利用线性调频脉冲进行帧同步的方法及性能     

马雯  黄建国  张群飞 《海洋技术学报》2006,25(3):86-89

针对水声信道的特点,提出了一种利用具有大的时宽带宽积的线性调频信号作为帧同步信号的方法。该方法首先在接收端进行滑动时频分析,从而实现线性调频信号的检测及粗同步,再进一步利用拷贝相关处理来实现细同步。计算机仿真和海上试验结果均表明,该方法能够在多途干扰下有效地实现同步。  相似文献   

振幅耦合动态网络中相邻结点间的相同步     

卢静  张荣  徐振源 《海洋学报》2010,32(9):5949-5953

研究用适当的量化指标来刻画动态网络的相同步,为此定义了新的量化指标:相邻结点的网络平均锁相值和网络平均相频差.动态网络结点选择的是多旋转中心的Lorenz混沌振子,对Lorenz系统进行柱面坐标变换,用振幅耦合方法构造动态网络.分别对星形网络和小世界网络进行了仿真计算,结果表明随着耦合强度的增大,网络中相邻结点的两个系统之间存在相同步现象,而且相同步行为与定义的量化指标之间存在较准确的对应关系.  相似文献   

临时验潮站深度基准面确定技术的改进     

郑行昭  付兴武  刘雷 《海洋测绘》2009,29(6):58-60

在临时验潮站深度基准面的传递推估中加入时间性的要求,再将潮差比法确定的深度基准面经同步改正,有效地提高了深度基准面的传递精度,并给出了评定其精度的可行方法。  相似文献   

混沌系统的变结构同步控制     

李自强  唐功友  李娟 《中国海洋大学学报(自然科学版)》2009,39(3)

研究Lorenz混沌系统的同步控制问题,提出1种在多输入的情况下实现混沌同步的变结构控制算法.利用该算法设计的变结构同步控制律使得同步误差系统的运动在切换面上成为渐近稳定的滑动模态,从而较快的实现了混沌同步.通过对 Lorenz 混沌系统的理论分析和数值仿真,说明了该变结构同步控制策略的实用性和有效性.  相似文献   

导航卫星精密定轨与时间同步技术进展     

周善石  胡小工  刘利  何峰  唐成盼  潘军洋 《天文学报》2019,60(4):57-66

全球卫星导航系统(Global Navigation Satellite System, GNSS)通过播发卫星钟差和精密轨道信息实现时间和空间基准信息向导航用户的传递.随着高精度原子钟等导航卫星载荷、星间链路等天基/地基监测手段以及数据处理方法等技术的不断更新,卫星轨道和钟差产品的精度和实时性也逐步提升. 2018年12月,北斗三号卫星导航系统正式开通,为"一带一路"国家提供实时高精度、高可靠的基本导航定位服务.综述了北斗导航系统从北斗二号区域系统到北斗三号全球系统精密定轨与时间同步处理面临的困难和挑战,针对上述问题,阐述了北斗运行控制系统的解决途径和实现指标.与GPS等其他GNSS系统进行比较,分析了不同导航系统技术特点.最后展望了精密定轨与时间同步技术未来的发展路线图,为更高精度的GNSS导航定位授时服务提供参考.  相似文献   

一种铷原子钟双钟热备相位无扰切换系统的设计     

邢彦超  杨俊  汤超  秦蕾  高伟  陈智勇  余钫  盛荣武 《时间频率学报》2011,34(2)

为了满足时间统一系统中主钟与备份钟的时间、频率信号在切换时的连续性要求,提出并实现了一种铷原子钟双钟热备相位无扰切换系统的技术方案,阐述了双钟间频率与相位同步和信号无扰切换的方案原理,给出了系统组成与主要控制程序的框图及测试结果。采用本方案可使主钟与备份钟输出信号的时差小于±0．55ns,并实现了信号的无扰切换,满足了工程应用的要求。  相似文献   

Contrasted hydrological responses to forest harvesting in two large neighbouring watersheds in snow hydrology dominant environment: implications for forest management and future forest hydrology studies          下载免费PDF全文

Mingfang Zhang  Xiaohua Wei 《水文研究》2014,28(26):6183-6195

Two large neighbouring watersheds, the Bowron (3420 km²) and Willow (2860 km²) situated in the central interior of British Columbia, Canada, were used to compare their hydrological responses to forest harvesting in snow‐dominant environment. Both watersheds had experienced significant, comparative forest harvesting level. The long‐term hydrometric and timber harvesting data (>50 years of records) were analysed using time series analysis to examine the hydrological impacts of forest harvesting. The hydrological variables including mean, peak and low flows over annual and seasonal scales (spring snowmelt, summer rain and winter base flow) were tested separately. Results showed that forest harvesting in the Willow watershed significantly increased annual and spring mean flows as well as annual and spring peak flows, whereas it caused an insignificant change on those hydrological variables in the Bowron watershed. The contrasted differences in hydrological responses are due to the differences in topography, spatial heterogeneity, forest harvesting characteristics and climate between two watersheds. The relative uniform topography and climate in the Willow watershed may promote hydrological synchronization effects, whereas larger variation in elevations, together with forest harvesting that occurred at lower elevations, may cause hydrological de‐synchronization effect in the Bowron watershed. The contrasted results demonstrate that the effects of forest harvesting on hydrology in large watersheds are likely watershed specific, and any attempt to generalize hydrological responses to forest harvesting must be carried out with caution. A landscape ecological perspective is critically needed for future forest hydrology studies, particularly for large watersheds. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Synchronization Theory and Tungsten-Polymetallic Mineralization Distribution in the Qianlishan-Qitianling Area,Southern Hunan     

李兵 《中国地质大学学报(英文版)》2011,(6)

Synchronization is an important frontier in contemporary nonlinear science.It has been developed and applied widely in the late 20th century.However,it has limited applications in geological science,especially in the study of mineralization.The ore formation of fluids is a problem of propagation of chemical waves and the generation of their spatiotemporal structures.Geological processes and spatiotemporal structures are the essence and core of all geological phenomena.Taking these ideas as guides,giving a n...  相似文献   

全站仪和GPS一体化测量方法探讨与精度分析     

程飞  张丽娜  张晓亮 《测绘工程》2014,(4):69-71

鉴于全站仪和GPS各自独立的特点,文中主要探讨全站仪与GPS一体化测量的过程,通过无线电传输实时处理数据,全站仪和GPS同步进行测量,文中对测量方法进行必要的精度分析,得出全站仪和GPS一体化测量能够适应多数测量作业,并且二者实时测量,能够避免全站仪换站的精度累计差,从而提高作业效率。  相似文献   

浅谈GPS/SINS组合导航系统的设计     

余卫国 《北京测绘》2014,(4):103-105

SINS/GPS组合导航系统是一种性能较好的导航系统,它结合了GPS的高精度定位,误差无积累及INS的自主性、实时性等优点。两者的结合可使导航系统的成本下降,可靠性增加,精度提高。本文概要地介绍了SINS/GPS的研究背景、结构组成、建立了系统的总体设计方案,给出详细的软件设计框图.并介绍实现系统各个功能的软件算法。实际应用结果表明:该系统的导航精度、成本、体积等指标均达到了设计要求。  相似文献