基于无线通信基站的室内三维定位问题

三维定位问题是现代商用通信网络中对于定位系统存在的一个真正具有技术难度的挑战.根据视距传播环境和非视距传播环境的到达时间的数据集,建立线性误差模型;对于无真实位置的竞赛数据集,定义竞赛数据定位误差评估模型;基于不同的空间场景,提出基于空间单元的定位算法;面对高度误差明显高于平面误差的问题,设计基于高斯加权的误差补偿模型;针对最优定位精度最少基站问题,提出基于贪心策略的基站选择算法;考虑轨迹连续性,设计轨迹准确性验证的10-fold交叉验证方法;基于测量距离有限的真实环境,分析平均"连接度数"与定位精度的关系.实验结果表明,提出的定位算法在有效基站数大于等于5时,能获得较好的定位精度.     

基于无线通信基站的室内三维定位问题研究

对基于无线通信基站的室内三维定位问题进行了研究,建立了测量误差模型和终端定位模型.建立了TOA测量误差模型和基于测量误差估计的终端定位模型,提出了基于空间几何约束和测量噪声抑制的定位算法;分别在相对时间误差、最大时延、最小时延和随机法四种基站筛选方案下,分析了不同基站数目对定位精度的影响;利用轨迹上相近点的信道状态信息的相关性,采用Kalman滤波算法计算了终端运动轨迹;基于假设性检验,通过递减迭代搜索算法,得到了可定位终端数;建立了基站不同覆盖范围下,终端连接度数与定位精度之间关系的分析模型.     

多基站下基于信号到达时间的室内三维定位

对基于无线电信号的到达时间(TOA)的定位技术进行了研究.首先,建立了TOA测量值与真实值间的函数关系,通过求解含惩罚项的非线性最小二乘问题实现终端定位和噪声估计,并在已有研究的基础上提出了Alternating Iterative Reweighting(AIR)算法;其次,利用基站之间的几何位置进行筛选,根据每个终端信息完成自适应的最少基站的选择及定位;并结合物理特性实现终端运动轨迹预测;最后,根据基站通信半径筛选出可被定位终端,完成定位精度与终端平均连接度数之间关系的建模.     

基于无线通信基站三维定位问题的求解模型

基于无线通信基站的三维定位相比于传统GPS定位有着诸多优势,技术有着广阔的应用前景和巨大的商业价值.针对基于无线通信基站的三维定位问题,首先分析建立TOA定位的初步模型.其次,基于对模型时钟误差、非视距传播误差、测量误差的分析,优化方程组的建立策略,基站排序,方程组系数修正的方式,使误差项的影响降到最小.最终由最小二乘法计算出定位结果.实验表明,定位模型的定位精度在1米左右,并且定位精度随基站数目的增多而增高.     

基于多元线性回归分析和Chan算法的三维精确定位研究

基于无线通信基站的室内三维定位问题主要是在已知TOA和基站三维信息的情况计算出终端的位置信息,实际上就是求解方程组中的未知数.首先建立通用模型和算法求解出终端的定位,接着通过优化得到使用尽量少的基站数目实现近似最优精度的定位,然后利用提出的算法实现终端移动轨迹的二维定位,最后结合实际情况,考虑了基站的有效测量距离并设计了有效基站识别算法对问题进行了分析.     

一种非视距环境下基于TOA三维定位的新方法研究

为消除非视距环境对TOA三维定位带来的误差,引入演化博弈模型,以各个测量基站作为博弈局中人,为非视距环境下的TOA三维定位问题建立了一般形式的复制动态模型.研究提出了基于演化博弈的TOA定位算法,通过迭代计算消除非视距误差,获得移动端的位置估计.进一步地,针对基站位置分布明显不均的情况,在演化博弈TOA定位算法的基础上,通过构造虚拟基站和虚拟测量值,提出了基于虚拟基站的三维定位算法.实验对比显示基于演化博弈的TOA定位算法略优于经典定位算法,在基站位置分布明显不均的情况下,基于虚拟基站的三维定位算法效果较明显.     

无线传感器网络三维定位算法

基于在传感器网络中基站能够测量未知节点(M)S发出的辐射到达不同基站的时间差和它们之间的相对角度,提出了一种基于TDOA/AOA混合三维定位算法,根据基站测得的到达时间差(TDOA)和到达角度(AOA),将两种信息进行融合,建立节点位置估计值的混合算法,得到三维空间内的无线传感器节点坐标.仿真结果表明:在AOA测量值精度比较高时,此种混合算法能够实现比其他算法更好的定位性能     

基于噪声误差模型的不规则区域室内定位和锚点分布优化

结合实际工业背景,研究了一类在不规则区域且误差不服从高斯分布的室内无线定位问题.给出了噪声误差模型, 在对多个传统定位算法进行性能分析的基础上,研究了待定位区域内锚点阵列的分布, 改进了多锚点阵列下的定位方法,并提出基于Delaunay三角剖分锚点分布优化模型和求解方法.     

有红利美式看跌期权定价树图模型的自适应性改进

本文基于支付固定红利美式看跌期权的三叉树图定价模型,对其进行了自适应性改进,从而解决了树图模型所存在的因为时间离散、状态不连续而产生的"非线性误差"问题.最后给出了实证分析,并与二叉树图和三叉树图进行了比较,结果表明进行自适应性改进后可以得到更加精确、有效的数值解.     

基于遗传算法的串联机械臂运动学参数标定

对机械臂的连杆参数进行标定可以有效减小由运动学参数不准确引起的机械臂定位误差.文章提出一种基于遗传算法的机械臂关节参数标定方法.首先建立机械臂运动学模型和误差模型,得到关节变量误差的表达式.通过NDI三维动态位移测量系统检测机械臂末端执行器的真实位姿以及各个关节实际旋转角度,作为样本.构建遗传算法的适应度函数,采用遗传算法计算出各关节变量的误差.最后,将该误差用于补偿六自由度串联机械臂真实的连杆参数,多组实验数据证明应用标定后的连杆参数完成机械臂的定位控制可以有效提高机械臂的绝对定位精度.     

Indoor positioning system based on BLE location fingerprinting with classification approach

Position estimation is an important technique for location-based services. Many services and applications, such as navigation assistance, surveillance of patients and social networking, have been developed based on users’ position. Although the GPS plays an important role in positioning systems, its signal strength is extremely weak inside buildings. Thus, other sensing devices are necessary to improve the accuracy of indoor localisation. In the past decade, researchers have developed a series of indoor positioning technologies based on the received signal strength (RSS) of WiFi, ZigBee or Bluetooth devices under the infrastructure of wireless sensor network for location estimation. We can compute the distance of the devices by measuring their RSS, but the correctness of the result is unsatisfactory because the radio signal interference is a considerable issue and the indoor radio propagation is too complicated to model. Using the location fingerprint to estimate a target position is a feasible strategy because the location fingerprint records the characteristics of the signals and the signal strength is related to the space relation. This type of algorithm estimates the location of a target by matching online measurements with the closest a-priori location fingerprints. The matching or classification algorithm is a key issue in the correctness of location fingerprinting. In this paper, we propose an effective location fingerprinting algorithm based on the general and weighted k-nearest neighbour algorithms to estimate the position of the target node. The grid points are trained with an interval of 2 m, and the estimated position error is about 1.8 m. Thus, the proposed method is low computation consumption, and with an acceptable accuracy.     

Numerical simulations of the improved Boussinesq equation

In this study, numerical simulations of the improved Boussinesq equation are obtained using two finite difference schemes and two finite element methods, based on the second‐and third‐order time discretization. The methods are tested on the problems of propagation of a soliton and interaction of two solitons. After the L_∞ error norm is used to measure differences between the exact and numerical solutions, the results obtained by the proposed methods are compared with recently published results. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010     

Modeling environmental effects on directionality in wireless networks

One method for improving wireless network throughput involves using directional antennas to increase signal gain and/or decrease interference. The physical layer models used in current networking simulators only minimally address the interaction of directional antennas and radio propagation. This paper compares the models found in popular simulation tools with measurements taken across a variety of links in multiple environments. We find that the effects of antenna direction are significantly different from those predicted by the models used in the common wireless network simulators. We propose a parametric model that better captures the effects of different propagation environments on directional antenna systems; we also show that the derived models are sensitive to both the direction of signal gain and the environment in which the antenna is used.     

ARTIFICIAL BOUNDARY METHOD FOR THE THREE-DIMENSIONAL EXTERIOR PROBLEM OF ELASTICITY

The exact boundary condition on a spherical artificial boundary is derived for thethree-dimensional exterior problem of linear elasticity in this paper. After this bound-ary condition is imposed on the artificial boundary, a reduced problem only defined in abounded domain is obtained. A series of approximate problems with increasing accuracycan be derived if one truncates the series term in the variational formulation, which isequivalent to the reduced problem. An error estimate is presented to show how the errordepends on the finite element discretization and the accuracy of the approximate problem.In the end, a numerical example is given to demonstrate the performance of the proposedmethod.