北斗卫星导航接收机的基本组成及设计思路探讨

北斗导航接收机能够获取精准位置信息,有助于位置管理系统最优化决策。在军事领域,提供精确制导等功能。介绍了北斗卫星导航基本原理,卫星导航定位算法;设计了卫星信号接收机的软硬件功能;对卫星定位精度算法进行了研究和分析,提出了高精度定位算法的时钟定时模块。     

基于快速拟合的高精度授时技术

本文针对采用晶振产生本地时钟的卫星导航接收机的高精度授时问题，特别是考虑在卫星失锁等不定位情况，提出了一种具备快速拟合的时间同步控制方法，提高了卫星导航接收机的授时精度和可用性。文中分析了影响卫星导航接收机授时精度的几个关键因素，给出了时间同步的软件设计算法实现，在某型卫星导航接收机上进行了测试验证。测试结果表明：本文设计的基于快速拟合的时间同步控制算法有效，提高了卫星导航接收机的授时精度和可用性。     

基于模糊区的卫星导航空时测量技术研究

卫星导航可为用户提供高精度的时间和空间数据测量能力,实现高精度定位、授时及校频等应用。在无源定位模式下,信号传播路径和接收机特征漂移率低,伪距观测量具有一定的稳定性和边沿效应,接收机可基于模糊区特性来获得瞬时高精度的位移和时钟漂移估计。在对卫星导航伪距观测量误差分析的基础上,提出一种实现接收机高精度时空相对信息测量的误差补偿策略,采用多观测量降低或消除伪距相关误差量,并基于模糊区及其边沿效应进一步提高相对信息测量的精度和稳定性。仿真分析了动态条件下的位移和时钟漂移测量精度,相关结果表明,基于模糊区稳定性及其边沿效应可提高接收机定位和时间相对信息的测量精度。     

多模复合接收机测试与评估体系研究

多模复合导航技术以其高精度的导航制导性能,在精确制导武器等领域获得了广泛的应用,随之带来了多模复合导航装备的测试评估的问题,传统的卫星导航测试技术难以满足其高精度、动态的测试需求,也缺乏针对基于卫星导航的相关应用性能测试手段。针对这一技术问题,通过对国外已建设的测试系统的技术分析,设计了一种基于伪卫星和导航模拟器的先进复合接收机综合测试评估系统,提出一种测试评估体系架构,分析研究了系统中所涉及的组合导航模拟、伪卫星系统基线网络等关键技术问题,基于外场测试环境提出一种构建方法并进行了分析评估。     

卫星导航专利分析报告之二——接收机高精度测量型天线

高精度测量型接收机在卫星导航应用产业属于高端产品,高精度测量型天线作为卫星导航接收机的重要组成部分,其性能直接关系到卫星导航接收机测量精度的大小。本文以大量的专利信息为基础,聚焦卫星导航终端高精度测量型天线中的三项主要技术:微带贴片天线技术、螺旋天线技术、扼流圈技术,对其产业现状和技术发展路线进行了梳理,全面呈现了高精度测量型天线领域的专利申请人特点、技术分支、重点专利及其引用关系。     

基于DSP/BIOS的多系统接收机主控系统设计

介绍了一种基于DSP/BIOS内核的多系统接收机主控系统设计与实现方法,利用DSP/BIOS内核基于任务优先级的多线程机制,实现对多系统接收机测量数据的实时处理,包括主控系统的任务调度、定位解算算法以及与设备的通信等。所设计的多系统接收机主控系统,已成功地应用到我国自主卫星导航定位系统多系统接收机中。     

国防科大四院 抓机遇、迎挑战、促发展

作为北斗系统建设国家队的核心主力,国防科大四院依托卫星导航定位技术工程研究中心(下简称"导航中心")突出"技术、产品、文化"参展特色,携带新型高性能卫星导航接收机、卫星导航信道模拟器、再生式导航信号转发器、便携式多功能干扰源、卫星导航基带芯片等新产品亮相第四届中国卫星导航学术年会,高精度及导航型新品推出引起业内广泛关注,特别是可以同时接收三种信号体制(北斗、GPS和GLONASS)、定位精度达到10米以内、应用前景广泛的新型高性能卫星导航接收机,以及高仿真度、高精度、高性能的卫星导航信道模拟器,受到多媒体报道,吸引了广大客户和重要厂商前来中心展台进行     

一体化BDS/GPS卫星导航接收机设计与实现

提出了一种一体化 BDS/GPS 卫星导航接收机设计方法，利用 Ansoft HFSS 仿真设计软件进行了天线设计，使用低噪声放大器、声表面滤波器、卫导芯片等较少的器件完成了卫星导航接收机的设计。并对设计的卫星导航接收机进行生产、调试和测试，给出了测试结果。结果表明，该一体化卫星导航接收机可满足使用要求。     

少星环境下的矢量跟踪接收机增强技术研究

卫星导航系统已经成为最常用的导航和定位手段,地面车辆、智能手机等都依靠卫星导航接收机提供高精度导航和定位信息.然而在城市复杂环境下,卫星导航信号常常被环境遮挡,接收机接收不到足够数量的卫星信号,导致接收机定位误差变大或者不能输出导航信息.矢量跟踪接收机采用卡尔曼滤波估计导航定位信息,能够在少星环境下提供一定精度的定位信息,但是误差随着时间发散.为了提高矢量跟踪接收机在少星环境下的性能,提出高度信息辅助矢量跟踪接收机方法,给出了高度信息辅助下矢量接收机导航信息估计模型.实际场景实验表明,在2 min的实验时间中,采用高度信息辅助,定位精度有了明显的提升.     

GPS卫星导航接收机调试工艺技术研究

对GPS卫星导航接收机调试工序的测试点及调试工艺技术进行了分析研究,明确了GPS导航接收机的调试工艺方法和步骤,有效规范、指导了卫星导航接收机系列产品的调试工作。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.