卫星导航空间信号用户测距误差评估方法

空间信号（SIS）精度是卫星导航系统的基本性能之一,而卫星的用户测距误差（URE）是SIS 精度的重要指标。基于轨道误差及钟差误差研究了GPS（全球定位系统）和BDS（北斗卫星导航系统）的SIS URE评估方法,并利用实测数据评估了GPS和BDS的SIS性能。验证结果表明：GPS的SIS URE均优于2.2 m,BDS SIS URE除GEO-01和GEO-04卫星外均优于2.5 m,符合GPS 标准定位服务性能规范（2008年）及北斗卫星导航系统公开服务性能规范（1.0版）对SIS URE的指标要求。     

GPS空间信号可用性评估算法

在民航等应用领域,卫星导航系统的可用性是决定其能否作为唯一或主要导航系统的关键性能指标。主要对GPS卫星导航系统的空间信号(SIS)可用性进行评估分析,研究一种基于马尔可夫过程的卫星导航单星可用性算法模型,并研究对卫星导航星座可用性的评估模型。结合GPS实测数据和GPS标准定位服务性能标准(GPS SPS PS)中的可用性指标,证明提出的空间信号评估模型有效且符合GPS SIS可用性指标要求。研究结果对我国北斗卫星导航系统可用性的评估具有一定的参考价值。     

GNSS空间信号精度评估方法

空间信号(SIS)精度是卫星导航系统的性能之一。针对目前精度评估模型存在的问题,提出了分段式SIS用户测距误差(URE)评估模型,并研究了SIS用户测速误差(URRE)、用户测加速度误差(URAE)评估模型,利用广播星历和精密星历评估了GPS和BDS的SIS精度性能。结果表明,除BDS C02卫星的URE以及GPS PRN10卫星的URAE略大以外,其余GPS和BDS卫星的SIS URE,URRE和URAE均符合各自系统的指标,验证了所提精度评估方法的有效性。     

GLONASS卫星导航系统的发展和现状

简要分析GLONASS（Global Navigation Satellite System)卫星导航系统的发展和现状,对该卫星导航系统的特点与GPS做出扼要比较。     

GPS III首星空间信号质量监测评估

GPS （Global Positioning System）在新一代卫星载荷中采用了大量新技术,首颗卫星成功发射后,官方尚未系统公布各导航信号的调制方式、复用方法等关键信息,因而其在轨测试阶段的空间信号质量评估具有重要的意义.该文选择地面接收功率、功率分配、相位关系、调制特性和测距性能等评估参数,深入分析了GPS III卫星L1频点空间信号质量,剖析了该卫星上多种新技术的信号特征.论文成果对其它GNSS（Global Navigation Satellite System）卫星载荷设计及信号体制设计等方面具有重要的参考意义.     

北斗卫星导航系统高精度定位的基本性能研究

引言 北斗卫星导航系统是中国自行研发的全球卫星导航系统,可在全球范围内全天时.全天候提供高精度的定位和导航等服务.本文对北斗卫星导航系统的高精度定位的基本性能进行了研究,通过分析其导航系统的广播星历数据,研究北斗卫星导航系统在不同纬度的可视情况,利用实测数据对其高精度定位的基本性能进行了分析和评估.北斗一代是一种区域有源卫星导航系统,覆盖的范围仅限于中国和周边国家和地区.而北斗二代在2012年正式投入使用,系统包含了5颗地球静止轨道卫星,5颗倾斜地球同步轨道卫星,4颗中国地球轨道卫星,共14颗卫星的定位系统.为此本文从伪距和载波相位观测、位置精度衰减因子、卫星可见性等多个方面评估其高精度定位的基本性能.并结合实测实验数据,对比分析其和GPS的性能对比.     

北斗卫星导航系统服务性能指标分析

北斗卫星导航系统服务性能指标是北斗卫星导航系统的关键技术指标,表示北斗导航卫星所能提供的服务水平。主要从覆盖性、精度、可用性、完好性和连续性几个方面来构建其指标体系;然后依据各个指标之间的相互关系,初步构建二级性能指标;最后通过软件仿真,对其性能进行了分析。     

适用于卫星导航电文的编码技术

对于卫星导航系统．采用先进的电文结构、高效的编码技术有利于提高导航系统的工作效率与可靠性。本文针对已有三大卫星导航系统（GPS．Galileo,GLONASS）进行了研究．对其导航电文结构与编码技术的发展进行阐述、比较与分析．在此基础上提出适用于北斗系统的QC—LDPC码。所设计的QC—LDPC码与GPS采用的LDPC友相比,前者抗误码性能更好．编码复杂度更低。并对我国自主研发的北斗系统的电文设计与编码方式提出可行性建议。     

一种基于北斗三号B2b信号的精密单点授时方法

授时是卫星导航系统的基本服务之一,在先进电子设备研制和智能时空信息服务中具有重要作用.针对当前全球卫星导航系统(Global Navigation Satellite System,GNSS)授时方法存在的受地面共视观测站和通信网络限制的问题,本文提出一种基于北斗三号B2b信号的精密单点授时方法(B2b signal ...     

从专利视角分析北斗卫星导航系统的发展

北斗卫星导航系统是我国自行研制并拥有自主知识产权的全球卫星导航系统,是我国重点发展的产业,从2000年开始建设北斗卫星导航试验系统,到2012年建成了覆盖亚太大部分地区并提供正式运行服务,至2017年完成23颗卫星的发射,并计划将在2020年左右完成由大约30多颗卫星组成的北斗全球卫星导航系统面向全球提供服务。然而,现有的GPS系统已经垄断定位行业达几十年之久,如何在短时间内赶超GPS系统,在行业中站稳脚跟,是北斗卫星导航系统全面发展面临的首要问题。本文着重分析了全球卫星导航系统所涉及的重要发展分支,从专利视角对比了北斗卫星导航系统和GPS系统在专利申请量方面的覆盖情况,并在此基础上为中国北斗卫星导航系统的发展指引方向。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first