长波/微波混合伪距导航定位模型研究

长波和微波的混合组合导航定位是当前导航系统发展的一个重要方向,但是由于长波距离计算的复杂性,目前还没有有效的定位模型进行计算.为此,首先从理论出发设计了长波/微波混合伪距定位模型,并解决了理论向工程转化中存在的计算问题;利用该模型与GPS导航模型进行相应的仿真和比对,仿真结果证明设计的模型不仅能够进行导航计算,而且可以保证比较好的精度.     

New FIR laser lines and frequency measurements in CD3OD

Twenty-four new submillimeter laser lines in fully deuterated methyl alcohol (CD₃OD) in the wavelength range from 52 to 328 m have been obtained in a Fabry-Perot FIR resonator by optically pumping the methanol with a cw CO₂ laser. We have made accurate wavelength measurements and have determined the relative polarization of most of the known CD₃OD laser lines. The frequencies of 13 of the strongest lines were also measured.Contribution of the U.S. Government, not subject to copyright.     

仪表的准确度等级与误差的关系

在日常计量器具检定工作中,计算检定结果时,常常会遇到误差计算以及通过计算误差来判断仪表准确度等级是否合格等问题.本文通过具体实例给出分析.     

基于最大特征根的相对效率的下界估计

定义了广义线性模型中参数的最小二乘估计（LSE）与最佳线性无偏估计（BLUE）的一种新的相对效率,这种相对效率定义为参数估计量的协方差阵的最大相对特征根之比。给出了当设计矩阵满秩,协方差阵非负定时这种新的相对效率的下界,研究了新的相对效率与广义相关系数之间的关系,由本文的而占可见,当广义线性模型与主成分分析、典型相关分析方法结合应用时,这种相对效率具有很强的实用价值。     

GPS移动车辆监控系统中的通信系统分析及仿真

耗资３００亿美元、历经了２０年才建成的ＧＰＳ系统是继阿波罗登月计划和航天飞机计划之后的第３项庞大空间计划,它从根本上解决了人类在地上的导航和定位问题,使导航和定位技术发生了巨大的变化。本文正是以ＧＰＳ移动车辆定位系统中的集群通信的数学模型,进行计算机仿真并根据仿真结果分析系统性能。     

Generalized binary discernibility matrix for attribute reduction in incomplete information systems

To extract and express the knowledge hidden in information systems, discernibility matrix and its extensions were introduced and applied successfully in many real life applications. Binary discernibility matrix, as a representative approach, has many interesting superior properties and has been rapidly developed to find intuitive and easy to understand knowledge. However, at present, the binary discernibility matrix is mainly adopted in the complete information system. It is a challenging topic how to achieve the attribute reduction by using binary discernibility matrix in incomplete information system. A form of generalized binary discernibility matrix is further developed for a number of representative extended rough set models that deal with incomplete information systems. Some useful properties and criteria are introduced for judging the attribute core and attribute relative reduction. Thereafter, a new algorithm is formulated which supports attribute core and attribute relative reduction based on the generalized binary discernibility matrix. This algorithm is not only suitable for consistent information systems but also inconsistent information systems. The feasibility of the proposed methods was demonstrated by worked examples and experimental analysis.     

变电站直流系统接地故障快速定位与预防措施

变电站直流系统不仅为全站继电保护类装置,同时还兼具二次回路提供电压,解析快速定位直流系统故障的方法,有利于检修人员快速处理故障问题,提升系统应用.     

Novel SREKF-based recurrent neural predictor for narrowband/FM interference rejection in GPS

The GPS provides accurate positioning and timing information that is useful in various applications. A new adaptive neural predictor for GPS jamming suppression applications is proposed. The effective and computationally efficient square-root extended Kalman filter (SREKF) algorithm is adopted to adjust the synaptic weights in the nonlinear recurrent architecture and thereby estimate the stationary and non-stationary narrowband/FM waveforms. Cholesky factorization is employed in Riccati recursion to improve numerical stability because of the propagation of round-off errors in conventional KF equations. The main characteristics of the proposed SREKF-based canceller are their rapid convergence and favorable tracking performance. Simulation results reveal that its SNR improvement factor exceeds the factors of conventional LMS, RLS, ENA and TLFN filters in single-tone CWI, multi-tone CWI, pulse CWI and FM jamming environments, respectively.     

高精度定位基准站验收方案探索

基于5G+北斗的高精度定位系统,主要包括GNSS卫星导航系统、地面基准站网络、软件服务平台等部分,通过输出差分校正值,为用户提供亚米级、(动态)厘米级、(静态)毫米级精度的定位服务。文章对高精度定位基准站的建设和验收方法进行了初步探索,提出了一种基于"总体图片检查"与“定点现场检查”相结合的验收方案。结合我司在多个省份的实践操作,该方案具有很好的可操作性,可极大提升验收效率,值得固化和推广。     

卫星定位中伪距的广义延拓外推

GPS当丢失部分伪距不能正常定位时,采用广义延拓外推法外推伪距来实现对用户位置的定位.仿真结果和理论推理表明,这种伪距外推法在外推步数一定的条件下能满足用户接收机定位的要求.