一种基于栅格预置点匹配的无线传感器网络目标定位方法

目标定位是无线传感器网络应用领域中一个重要的问题,是进行目标跟踪的前提和基础.节点呈栅格部署的无线传感器网络由于拓扑结构特殊,在目标定位应用领域具有独特的优势.本文基于栅格部署的无线传感器网络,提出了栅格预置点目标定位方法,通过设定和选择合适的栅格预置点进行目标定位.仿真实验和实际测试实验表明,该方法在定位准确性和实时性方面较先前的单层栅格定位和双层栅格定位都有较大幅度的提高.     

室内定位技术及应用综述

室内定位技术作为当前的研究热点,对军事、经济以及人们的日常生活产生了深远的影响。文中首先介绍了室内定位技术的应用背景以及发展方向,以及室内环境进行定位面临的主要难点。然后介绍了目前主要的定位算法,包括邻近信息、场景分析和几何定位算法,以及各种算法衍生出来的各种定位技术。最后指出了室内定位技术亟待解决的问题,以及下一步进行相关研究的突破口。     

一种基于双圆域的AUV自主导航定位精度计数考核方法

导航定位精度是自主水下航行器（AUV）一项重要的技术指标。基于概率圆计数考核方法,取概率圆半径较小时,当AUV的导航精度远低于指标时不利于快速做出判定;而取较大时,当AUV导航系统存在较大的系统偏差仍有可能判定为合格。针对上述不足,该文根据AUV的基本轨迹及其航行轨迹测量的特点,提出了一种基于双圆域的AUV导航定位精度计数考核方法,通过研制方和用户方风险共担的原则合理调整2个圆域的半径,不仅可以在AUV实际导航定位精度远低于指标要求情况下进行快速判定,而且有助于降低导航系统的系统误差对考核的影响。仿真验证表明,该方法科学、合理,具有工程应用价值。     

基于领弹-从弹架构的无导引头导弹协同定位与制导方法

针对无导引头导弹在采用现有制导律时定位误差会产生较大脱靶量的问题,通过双领弹的领弹-从弹协同架构,设计了一种协同定位与制导策略,以实现无导引头导弹对静止目标的精确命中。基于扩展卡尔曼滤波,提出了一种无导引头导弹的协同定位方法。该协同定位方法与比例导引结合时存在终止时刻过载指令过大问题,因此设计一种新型变系数比例导引律,分析了变系数比例导引律的制导系数对脱靶量、终止时刻过载与最大过载的影响。仿真结果表明：采用所提出的协同定位方法可减小具有定位误差的无导引头导弹脱靶量,而采用变系数比例导引律可避免终止时刻过载指令过大。     

一种改进的测试芯片的设计方法

集成电路制造技术的不断进步,给缺陷定位带来巨大的挑战。传统的测试芯片和现有的可寻址的方法都无法满足当前缺陷快速准确定位的要求。本文提出了一种改进的可寻址测试芯片的设计方法:每个测试结构采用四端法连接以及单一的NMOS晶体管作为开关电路,以保证电性测量结果精确、电路设计的简洁以及面积利用率的进一步优化;并利用开关电路增加少量测试引脚,以方便物理缺陷定位的进行。该方法在110nm的CMOS工艺中得到应用。经过实际生产验证,实现了金属层断路等缺陷的定位,有效发现了该工艺中失效缺陷的成因,从而帮助实际的成品率实现快速提升。     

真实环境中基于子帧分析的多说话人定位算法

针对真实环境中的多说话人定位问题,提出一种基于子帧分析的多声源定位算法。该算法将一帧语音信号分为8个子帧,利用每个子帧信号计算相位变换加权的可控响应功率函数,分别搜索其最大值得到声源位置的子帧估计。由于语音信号在时域具有稀疏性,这些估计值对应多个声源的位置。利用会聚聚类算法将子帧估计值分为若干类,然后用平均子帧可控响应功率函数对估计值进行评价,得到最终的声源位置估计。实验表明,在2~3个说话人的情况下,该算法比传统算法的定位性能有较大幅度提高。     

Self-repairing adder using fault localization

In this paper we propose an area-efficient self-repairing adder that can repair multiple faults and identify the particular faulty full adder. Fault detection and recovery has been carried out using self-checking full adders that can diagnose the fault based on internal functionality, independent of a fault propagated through carry. The idea was motivated by the common design problem of fault propagation due to carry in various approaches by self-checking adders. Such a fault can create problems in detecting the particular faulty full adder, and we need to replace the entire adder when an error is detected. We apply our self-checking full adder to a carry-select adder (CSeA) and show that the resulting self-checking CSeA consumes 15% less area compared to the previously proposed self-checking CSeA approach without fault localization. After observing fault localization with reduced area overhead, we utilize the self-checking full adder in constructing a self-repairing adder. It has been observed that our proposed self-repairing 16-bit adder can handle up to four faults effectively, with an 80% probability of error recovery compared to triple modular redundancy, which can handle only a single fault at a time.     

Cooperative localization techniques for wireless sensor networks: free,signal and angle based techniques

This paper addresses the problem of localization in sensor networks where, initially, a certain number of sensors are aware of their positions (either by using GPS or by being hand‐placed) and are referred to as anchors. Our goal is to localize all sensors with high accuracy, while using a limited number of anchors. Sensors can be equipped with different technologies for signal and angle measurements. These measures can be altered by some errors because of the network environment that induces position inaccuracies. In this paper, we propose a family (AT‐Family) of three new distributed localization techniques in wireless sensor networks: free‐measurement (AT‐Free) where sensors have no capability of measure, signal‐measurement (AT‐Dist) where sensors can calculate distances, and angle‐measurement (AT‐Angle) where sensors can calculate angles. These methods determine the position of each sensor while indicating the accuracy of its position. They have two important properties: first, a sensor node can deduce if its estimated position is close to its real position and contribute to the positioning of others nodes; second, a sensor can eliminate wrong information received about its position. This last property allows to manage measure errors that are the main drawback of measure‐based methods such as AT‐Dist and AT‐Angle techniques. By varying the density and the error rate, simulations show that the three proposed techniques achieve good performances in term of high accuracy of localized nodes and less energy consuming while assuming presence of measure errors and considering low number of anchors. Copyright © 2012 John Wiley & Sons, Ltd.     

基于邻居节点相似度的改进DV-Hop节点定位算法

针对DV-Hop定位算法存在的定位精度较低的不足,提出了邻居节点相似度概念,克服了DV-Hop定位算法中节点间距离区分度单一的缺点,同时在多跳通信中,考虑了通信路径的情况,将DV-Hop算法直接计算折线距离代替实际中直线距离这一不足,采用余弦定理和邻近节点相似度对其进行修正。从而实现了对DV-Hop算法的改进,提高了定位精度。最后对改进后的算法和DV-Hop算法以及参考文献中的算法进行仿真比较,结果表明:改进后的算法较DV-Hop算法在节点定位精度上提高了30%以上。     

近场MVDR聚焦波束形成被动定位方法

该文系统地研究了最小方差信号无畸变响应（MVDR）聚焦波束形成方法的定位性能,特别是对该方法定位性能受某个参数的影响情况进行了较详细的研究。首先分析了近场情况下线列阵接收信号的模型,然后分别推导了常规聚焦波束形成和MVDR聚焦波束形成的定位原理。仿真比较了这两种定位方法的定位性能,以及MVDR聚焦波束形成被动定位方法在不同的阵元间距和不同的目标距离情况下的定位性能。仿真结果表明,与常规聚焦波束形成相比,MVDR近场聚焦波束形成在提高分辨率的同时,减小了＂混叠＂影响,具有更为平滑的背景和更低的旁瓣级,同时认为,为了得到比较好的定位效果,目标应处于相对于＂近场＂的位置,从而为目标精确定位提供依据。