Hierarchical sampling optimization of particle filter for global robot localization in pervasive network environment

This paper presents a hierarchical framework for managing the sampling distribution of a particle filter (PF) that estimates the global positions of mobile robots in a large‐scale area. The key concept is to gradually improve the accuracy of the global localization by fusing sensor information with different characteristics. The sensor observations are the received signal strength indications (RSSIs) of Wi‐Fi devices as network facilities and the range of a laser scanner. First, the RSSI data used for determining certain global areas within which the robot is located are represented as RSSI bins. In addition, the results of the RSSI bins contain the uncertainty of localization, which is utilized for calculating the optimal sampling size of the PF to cover the regions of the RSSI bins. The range data are then used to estimate the precise position of the robot in the regions of the RSSI bins using the core process of the PF. The experimental results demonstrate superior performance compared with other approaches in terms of the success rate of the global localization and the amount of computation for managing the optimal sampling size.     

基于ZigBee的室内无线定位系统的设计

为了使监控中心对AGV(Automated Guided Vehicle)的运行进行更精确的定位监控,设计了一种基于ZigBee的室内无线定位系统。首先完成了无线定位系统的硬件设计。然后考虑功耗成本精确度等方面,文章采用基于RSSI(Received Signal Strength Indication,接收的信号强度指示)的三边定位算法实现定位。同时为了更好的提高定位的精确度,采取了差分修正算法。最后进行了测试。测试结果表明,本设计可以实现监控中心对AGV的实时定位,并且系统的功耗较小成本较低精度也较高。     

基于修正 RSSI 值的四边形加权质心定位算法

在利用接收信号强度指示(RSSI)对无线传感器网络中的未知节点进行定位时,RSSI 值易受环境的影响导致定位误差, 为此提出基于 RSSI 测距修正的四边形加权质心定位算法(QWCRC)。 先对来自同一锚节点的多个 RSSI 值进行卡尔曼滤波,得 到修正的 RSSI 值,致使测距尽可能的接近真实距离;再采用四边形加权定位对未知节点进行定位,同时利用最小二乘法进行辅 助定位,此算法对于相邻锚节点圆不相交的情况给出新的解决方案。 实验结果对比表明,改进的算法相比较于四边形加权质心 算法(QWC)和 RSSI 测距修正的三角形加权算法(TWCRC),在锚节点数目 5×5 和噪声强度为 0 dbm 时,定位精度可分别提升 87. 14%和 35. 51%。     

煤矿安全监测无线传感器网络节点定位技术

利用无线信号强度实现了煤矿安全监测无线传感器网络节点间的自定位，提出了提高定位精度的改进方案，并分析了不同因素对定位精度的影响．仿真结果表明，所提出的算法可以有效地提高无线传感器节点的定位精度，如在路径损耗标准偏差分别为4和6，滚动平均次数为10时，定位精度的相对误差分别从0.21和0.35左右下降到0.18和0.29左右.     

WMSRS系统定位技术的研究和实现

无线矿井生命安全与救援系统（WMSRS．Wire less Mine Secure and Rescue System）是基于RFID（Radio Frequency Identification）综合应用WSN（Wireless Sensor Network无线传感器网）、RFID．WLAN、SDR（Short Distance Radio短距离无线通信设备）技术相结合实现一套高效、高可靠性、低成本．们设容易的无线矿升安全与救援系统系统结构如图1所示。     

基于RSSI的改进质心定位算法

为提高无线传感器网络三角形质心定位算法的精度,提出一种基于RSSI的改进质心定位算法.首先,分析传统基于RSSI的三角形质心定位模型,发现单个锚节点测距误差较大会导致盲节点的定位精度受到影响,因此采用4点进行定位来降低单个锚节点权重;其次,改进的质心定位算法选择根轴相交组成的区域作为定位参考区域,将该区域的质心位置作为待测盲节点位置;最后,采用仿真实验对比算法的精确度和稳定性,实验结果表明,相比于传统算法,改进算法定位精度更高,而且定位误差波动更小.     

基于接收信号强度的雷场节点定位方法

为了减少封锁雷的硬件设备及降低功耗,提出了一种基于接收信号强度测距的雷场节点定位方法.该方法只需通过封锁雷本身的无线通信模块,不增加任何外界设备.首先根据接收信号强度RSSI测得雷场节点间的距离,通过数学运算建立虚拟锚点,然后借助已建立的锚点和三边测量法来确定锚点附近未知节点的坐标,直到雷场所有未知节点都计算完毕,最终完成雷场节点间的相对定位.实验结果表明当信道损耗指数为2.5时测距误差最小,雷场节点定位误差在4m以内,满足雷场封锁要求.     

基于ZigBee 的RSSI 测距模型

针对现有国内外定位技术的不足,设计一种基于RSSI测距的定位方法。通过对室内无线信号的传播特性和室内测距模型进行相关研究工作,分析环境对RSSI的影响,在确定传播损耗模型后,根据实测数据筛选并计算得到满足实际环境的参数值。测验结果表明:该模型较为准确地反映了RSSI与距离的关系,为测距技术在无线定位系统的应用奠定了基础。     

Environmental-adaptive indoor radio path loss model for wireless sensor networks localization

In the received signal strength indicator (RSSI) based indoor wireless sensor networks localization system, RSSI measurements are very susceptible to multipath fading, anisotropy of antenna, low supply voltage of node and so on, which will cause the system failure to achieve a high location accuracy. This paper presents an environmental-adaptive path loss model. In the process of localization, the calibrated coefficient LSV of low supply voltage, which can be determined by monitoring the supply voltage of the sender, is used to calibrate ranging errors caused by its low supply voltage. The blind node utilizes the absolute value of RSSI to generate the phase of the corresponding receiver's location so as to determine the correction coefficient of indoor multipath fading R_i. Furthermore, in order to improve the accuracy of RSSI measurements, we also take full consideration of the effect of antenna to accurately determine the corresponding path loss model of the two communication nodes. The proposed path loss model is suitable for the majority of wireless location systems that are on the basis of RSSI-based ranging techniques. Experiment results show that the estimation accuracy and adaptability of the proposed path loss model are significantly higher than that of the traditional one.     

采用RSSI提高无线传感网络定位精度的算法

为了提高无线传感网络中节点的定位精度,同时又希望降低节点的定位开销,提出接收信号强度(RSSI)定位算法。以RSSI和三边定位原理为基础,详细阐述了该算法的定位思想,以伪代码的形式描述未知节点定位的实现过程。从存储、计算和通信开销3个方面与ALA方案做了定性分析,针对不同的冗余系数、不同的定位轮数和不同的信标数量进行了仿真,与ALA方案做了定量分析。分析结果表明,该算法达到了提高无线传感网络定位精度的目的。