GLONASS载波相位整周模糊度分析

由于GLONASS系统信号频率的差异,在载波测量数据处理中不能采用与GPS载波相位测量数据相同的方法,GLONASS整周模糊度的解算便成了一个难点问题。本文对GLONASS载波相位测量整周模糊度解算的基本思路和方法进行了介绍。     

无人机中磁航向自修正应用

以无人机组合导航系统为研究背景,针对磁传感器的误差校准方法,以及校准后磁航向误差进行研究。通过分析磁传感器误差来源,给出水平面内椭圆直接拟合模型。考虑磁传感器修正后的磁航向与GPS航迹角之间存在一定误差,建立航向误差角与磁航向之间的学习函数,从而辅助在GPS丢失情况下,采用学习后的磁航向来辅助无人机导航。飞行实验结果表明,利用该文采用的椭圆模型以及自学习函数,能够提高磁航向精度,从而可以辅助无人机在GPS丢失情况下航向解算。     

GPS载波相位测量中的几个重要问题

利用GPS载波相位信息可以达到精密导航定位,本文对GPS载波测量时整周模糊解算方法和周跳的检测与恢复进行了研究,阐述了解模糊的Ex-tradwingding技术和模型函数法,重点研究了利用卡尔曼滤波技术实现“on-thfly”解模糊算法。     

GPS姿态测量中的整周模糊度的实时解算方法

GPS 实时姿态测量的核心问题是整周模糊度解算。本文提出了一种适合实时姿态测量的模糊度解算方法,它利用单差平滑伪距进行解算,与传统的模糊度解算方法相比具有许多优点。该方法的有效性和实用性通过仿真实验进行了验证。     

导航、电子对抗、制导

TN966 2004061372一种用INS辅助GPS周跳检测和求解整周模糊度的方法/赵伟,万德均,(2}刘建业(东南大学)11中国空间科学技术一2 004,24(2).一13一18在INS/GPS全组合导航系统中,需要利用GPS载波相位测量信息、其中整周模糊度的确定和周跳的检测是两个关键的技术.文中提出了利用INS信息对GPS解算过程中的周跳检测和整周模糊度的确定进行辅助解算的简易快速算法,并进行了计算机仿真.仿真结果表明,文中提出的INS辅助GPS的周跳检测简易算法可以有效的检测出发生的小到一周的周跳;在一定条件下,利用INS信息辅助GPS可以瞬时可靠地求解…     

一种新的GPS快速整周模糊度解算算法

本文实现了一种新的GPS快速整周模糊度解算算法,首先采用Kalman滤波估计初始浮点模糊值,然后采用FASF（快速模糊度搜索滤波器）和Z变换联合的方法解算整周模糊度,并给出了计算机实验结果。相对于传统的模糊度解算算法,本文采用的整周模糊度解算方法具有效率更高、更便于实时和动态应用的特点,本文的研究可作为GPS实时高动态定位和GPS实时姿态测量的工程应用的参考。     

基于GAMIT的基线解算应用探究

GAMIT基线解算是GPS数据分析和处理的重要方法。本文主要介绍利用虚拟的linux系统,以GAMIT软件进行精确定位、基线解算的批处理过程。对GAMIT软件安装过程进行详细的介绍,并利用基站的数据信息进行基线解算,对结算结果进行分析并得出结论。目的在于解算后能形成模块以进行不同点的精确定位。     

基线约束辅助整周模糊度求解研究

本文对GPS领域中的整周模糊度求解的问题进行了详细的研究,利用Z变换和基线信息的约束和更新,对传统的快速整周模糊度搜索(FASF)的方法进行改进,并给出了相应的实验结果.实验结果表明,相对于传统的FASF方法,本文采用的整周模糊度解算方法能有效的缩小可能的模糊值状态集合,从而减少了解算的时间,适合于在动态的环境下实时运用.     

目标航向航速解算及验证方法研究

主要论述了在雷达产品应用中对海空目标相对和绝对航向航速的解算方法,并对几种可以提高航向航速解算精度的方法进行了探讨,最后提供了一种验证相对和绝对航向航速解算精度的方法。     

基于DSP的GPS定位解算算法研究与实现

采用TI公司的TMS320C6713DSP芯片实现了GPS接收机定位解算功能。利用该芯片实现GPS接收机各模块的调度,完成对时间观测量和导航电文的提取,进行卫星位置解算和用户位置解算以及对外接口。试验结果表明,根据该方案设计的GPS接收机工程样机可以准确地实现定位解算功能。     

基于载体姿态的GPS信号模拟器

GPS姿态测量技术是根据安装在载体上的多天线阵所确定的基线平面来推算出载体的航向及姿态原理。通过将载体姿态信息反映在其多天线阵接收信号状态上,并形成测姿所用的观测文件,以实现对测姿接收机在各种环境条件下的灵活测试。提出了GPS姿态信号模拟的原理设计方案,同时进行了建模与仿真分析,包括从姿态信号生成模拟、多天线阵定位解算到载体姿态解算的一系列完整过程。仿真结果表明,三维姿态角标准差都在0.2°以下,符合实际情况。     

Interaction of 10.6-µm radiation with current carriers in germanium

The absorption of 10.6-µm energy by excess carriers in germanium is used to study carrier density profiles within the bulk of intrinsic materials. Excess carriers are injected into blocks of germanium. The material is probed by an optical beam from a CO2laser and the energy in the exit ray is measured to determine carrier absorption. Carrier density in the material is found to correspond to two distinct patterns. The determination of carrier cross section is discussed.     

Charge extraction by a linearly increasing voltage of photo-generated carriers: The influence of two mobile carrier types,bimolecular recombination,and series resistance

The charge extraction by a linearly increasing voltage (CELIV) technique is a well-known and commonly used method to characterize charge transport in low-mobility materials. In the original CELIV theory it is assumed that one type of charge carrier is mobile and the other fixed and that recombination during the extraction pulse is negligible. However, this is in general not the case, especially in photo-CELIV where both electrons and holes are generated by light excitation. Moreover, RC effects induced by the series or load resistance of the external circuit are typically assumed to be negligible. In this work, we use drift-diffusion modelling and analytical derivations to show that the standard equations used for calculating the mobility in the moderate conductivity regimes generally leads to errors in the mobility determination in the case when i) two carrier types of similar mobility, ii) recombination, iii) an electric-field-dependent mobility, and iv) RC effects are present in the device. The effect of the external series resistance on the mobility determination becomes of particular importance in devices with relatively large mobilities and/or high carrier concentrations, where the original CELIV theory might give rise to an underestimation of the mobility by several orders of magnitude.     

通信电缆断点载波测试单片机控制系统设计

介绍玫种采用单片机控制和通信电缆断线故障实时载波测试装置,包括硬件组成及软件设计方法,并给出实验室条件下进行载波模拟测试的结果：断点位置确定基本正确。该方法较之传统方法具有在线载波检测、断点位置确定精度较高、操作简便等优点。     

Space flight tests of attitude determination using GPS

Preliminary space flight results of attitude determination using GPS are presented from a spacecraft in low Earth orbit. Relative position measurements accurate to the sub-centimetre level are made among multiple GPS antennas mounted on the space vehicle. A Trimble Navigation TANS Quadrex (a GPS receiver specially adapted for attitude determination by Stanford University) is used as a differential carrier phase sensor for the flight. Four GPS antennas are mounted on the zenith face of RADCAL, a polar orbiting, gravity-gradient-stabilized Air Force Space Test Program Satellite, built by Defense Systems, Inc. The four antennas are equally spaced about the perimeter of the 30 inch diameter cylindrical spacecraft bus. The Quadrex receiver measures the phase of the L-band GPS carrier (1575 MHz) at each of up to four antennas for up to six GPS satellites simultaneously. From these measurements, an initial assessment of attitude determination in space is performed in post-processing. For RADCAL, the attitude solution is greatly overdetermined. In a preliminary evaluation of system performance, the system accuracy is determined through measurement self-consistency. Analysis of the attitude motion in the context of a gravity gradient dynamic model yields further insight into the system performance.     

重掺杂发射区中禁带宽度和少子复合寿命的确定方法

禁带宽度和少子复合寿命是硅晶体管发射区中重要的物理参数。本文利用p-n结反向扩散电流的温度特性和借助于线性外推法,提出了一种确定绝对零度时禁带宽度的新方法。由于发射区重掺杂,本文考虑了载流子的费米-狄拉克统计分布。提出了确定发射区中少子复合寿命的方法。该方法简便实用。     

Measurement of charge-carrier behaviour in PIN diodes using a laser technique

A measurement system for the determination of charge-carrier densities in operating power devices is described. The system is computer-controlled and uses the free carrier absorption at 3.39 μm wavelength to deduce charge densities as a function of space and time. Measurements of carrier distribution in PIN power diodes have enabled derivation of the ambipolar diffusion length, the carrier lifetime and the carrier mobility.     

Control of the Interworking Between Packet Reservation Multiple Access and Dynamic Carrier Allocation

This work deals with an enhanced frequency division multiplex/packet reservation multiple access (FDM/PRMA) technique for cellular systems also suitable for wireless local area networks (WLANs); such enhancements consist of an efficient control of the interworking between dynamic carrier allocation (DCA) strategies, which guarantee a real-time rearrangement of the carriers-to-cells assignment and PRMA techniques. This allows a higher carrier exploitation. In this respect, the novelties introduced in this paper are: (i) the definition of a short-term packet dropping probability which permits the real-time assessment of the link quality of a PRMA carrier; (ii) the determination of a procedure the base station (BS) can follow in order to perform a real-time estimation of the above-mentioned short-term parameter; (iii) an efficient carrier management and interworking between the DCA mechanism and the PRMA technique realized by means of such parameter. The paper also shows simulation results highlighting a remarkable improvement of the carrier utilization, obtained by the proposed interworking of the DCA and PRMA techniques.     

Algorithm of SAR satellite attitude measurement using GPS aided by kinematic vector

In this paper,in order to improve the accuracy of the Synthetic Aperture Radar (SAR) satellite attitude using Global Positioning System (GPS) wide-band carrier phase,the SAR satellite attitude kinematic vector and Kalman filter are introduced.Introducing the state variable function of GPS attitude determination algorithm in SAR satellite by means of kinematic vector and describing the observation function by the GPS wide-band carrier phase,the paper uses the Kalman filter algorithm to obtian the attitude variables of SAR satellite.Compared the simulation results of Kalman filter algorithm with the least square algorithm and explicit solution,it is indicated that the Kalman filter algorithm is the best.     

Measurement of Auger recombination in silicon by laser excitation

A new experimental arrangement for the study of Auger recombination in silicon is described and analyzed. A relatively weakly absorbed YAG:Nd laser beam was used for excitation. The decay of the carrier concentration after the injection pulse was studied by measuring the recombination radiation in a direction perpendicular to the laser beam. At some distance from the injection surface the influence of surface recombination and diffusion is then negligible. It has previously been shown that in this geometry the carrier concentration distribution after the laser excitation is accurately described by an analytical expression which accounts for attentuation of the laser beam by both interband and free carrier absorption. Thus the local carrier concentration in the sample can be computed to a high degree of accuracy, which is essential in the determination of the Auger recombination coefficient from decay measurements. Furthermore, this experimental geometry eliminates the problems with laser stray light. Assumptions regarding the influence of surface recombination and diffusion are not necessary in the interpretation of the experiments. The method is usable for silicon in the temperature interval 150–400 K. Preliminary measurements of the Auger coefficient at room temperature are reported.