BPL工作钟信号T(PU)的监控方法研究

中国科学院国家授时中心(NTSC)BPL长波授时台升级改造项目要求实现BPL系统的工作钟信号T(PU)的自动监控.T(PU)的控制指标为T(PU)与NTSC时频基准实验室的主钟信号UTC(NTSC)之间的相位时间差的绝对值| UTC(NTSC)-T(PU)|小于50 ns;T(PU)的频偏绝对值优于5×10-13.为达到上述指标,并尽可能提高T(PU)的准确度,研究了在采用不同类型的原子钟作为工作钟频率源时所需采用的T(PU)的监控方法.结论是对日稳较好的频率源,用对工作钟频率源的频偏进行准实时预报得到的值和实测得到的相位时间差UTC(NTSC)-T(PU)来计算应该加到相位微调仪上的频率补偿值,从而进行工作钟的频率驾驭,可以大大提高工作钟信号T(PU)的准确度;而对不太稳定的频率源,频偏准实时预报准确度很差,采用几个月时间段内的平均频偏以及实时实测的相位时间差来进行频率驾驭,以便确保T(PU)的准确度.     

~(87)Sr原子束的塞曼减速器磁场的研究

应用塞曼效应和多普勒冷却的理论,结合实验条件计算了87Sr原子束塞曼减速器的磁场.数值模拟给出了磁场线圈的层数、圈数、供电电流和其他参数,并据此制作了纺锤状线圈.测量结果表明,研制的纺锤状线圈的轴向磁场满足87Sr光晶格钟实验的要求.     

基于量子纠缠时钟测量的抗差卡尔曼卫星钟差预报

基于纠缠光子对二阶相关函数的时间特性分析,设计时钟同步测量方案,并考虑传播过程中色散效应及衰减等对精度的影响。该方案可提供均值1 ns、精度0.01 ns的同步信息。利用该方案获得观测数据,结合顾及哈达玛方差的抗差卡尔曼方法估计出卫星钟差模型系数,进行钟差预测。仿真表明,该方案预测精度与IGS预报星历产品精度相当,且钟差初始值更精确。     

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基于混沌加权一阶局域法的IGS超快星历钟差预报

为提高IGS超快星历钟差预报产品的精度,针对卫星钟差数据具有确定项和随机项成分的特点,在采用多项式模型对钟差确定项建模的基础上,提出采用混沌加权一阶局域法对钟差随机项进行建模预报。仿真结果表明,采用混沌加权一阶局域法的预报精度优于超快星历钟差预报产品。     

Reparameterization of single difference and undifferenced kinematic GPS positioning models

A series of advantages of single difference(SD)and undifferenced(ZD)models are given as compared with the double difference(DD)model.However,rank defects exist in SD and ZD models.The reparameterization method is provided to resolve this rank defect problem by estimating some combinations of the unknowns rather than the unknowns themselves.The reparameterization of SD and ZD functional models is discussed in detail with their stochastic models.The theoretical confirmation of the equivalence of undifferenced and differenced models is described in a straightforward way.The relationship between SD and ZD residuals is given and verified for some special purposes,e.g.research on the stochastical properties of GPS observations.     

矩阵标准化求秩的计算机解法

矩阵求秩的方法比较复杂,目前尚未见到成熟的固定子程序。本文提出了“矩阵标准化求秩的计算机解法”。通过矩阵的标准形获得矩阵的秩,是一种普遍适用的计算机快速求秩方法。本文介绍了此算法的原理,并用FORTRAN—77结构化程序设计语言编写出此算法的通用子程序,同时给出调用实例。     

AN IMPROVED ALGORITHM FOR THE GENERALIZED RANK ANNIHILATION METHOD

An improved algorithm for the generalized rank annihilation method(GRAM)is presented.GRAM isa method for multicomponent calibration using two-dimensional instruments,such as GC-MS.In thispaper an orthonormal base is first computed and used to project the calibration and unknown sampleresponse matrices into a lower-dimensional subspace.The resulting generalized eigenproblem is thensolved using the QZ algorithm.The result of these improvements is that GRAM is computationally morestable,particularly in the case where the calibration sample contains chemical constituents not present inthe unknown sample and the unknown contains constituents not present in the calibration(the mostgeneral case).     

准噶尔和吐哈盆地株罗系煤层气储集特征

西北侏罗纪陆相盆地低煤级煤层气藏勘探开发近年来受到越来越多的关注,煤层气成藏机制是该区煤层气勘探开发的重要基础工作,而煤层气储集是煤层气成藏的关键地质过程。研究表明:准噶尔、土哈两个侏罗纪陆相盆地低煤级煤储层具有高孔容、高孔比表面积、高游离气储集潜力和低原位吸附气体能力的特征,深部煤储层储集气量显著高于浅部煤储层;浅部煤储层中基本上为吸附气,深部煤储层中吸附气、游离气、溶解气共存,游离气的重要性随埋深增加而增大;构造高点和构造圈闭对深部煤层气成藏具有重大影响,煤层气与常规气兼探与共采在理论上可行,深部煤层气藏可能较浅部煤层气藏更具开发价值。