多功率移动锚节点辅助的分布式节点定位方法

提出了一种移动锚节点辅助的分布式定位算法.与以前的基于移动锚节点的定位算法不同,此算法不需要任何测距技术支持.它是利用移动锚节点的功率控制,即以不同的发射功率发射信标信号,接收到信标信号的未知节点将这些信标信息转化为一系列二次不等式约束,然后通过凸优化技术求解这些不等式组来逼近未知节点位置的最佳估计.仿真结果表明,提出的距离无关的定位算法可适合实际定位情况且具有较高的定位精度.     

基于连通度和加权校正的移动节点定位算法

移动节点定位问题是无线传感器网络中的研究重点。针对移动节点定位误差大的问题,提出一种基于连通度和加权校正的移动节点定位算法。在未知节点移动过程中,根据节点间连通度大小选取参与定位的信标节点,利用加权校正方法修正RSSI测距信息,然后用最小二乘法对未知节点进行位置估计。仿真分析表明,节点通信半径和信标密度在一定范围内,该算法表现出良好的定位性能,定位精度明显提升。     

多移动信标辅助的分布式节点定位方法

为提高移动信标辅助定位算法的定位精度,避免重复扫描待定位节点,提出了一种使用多个移动信标的定位方法。这些信标在遍历网络时保持一定相对位置关系,使用TDoA技术测距并为未知节点提供距离信息辅助其定位。提出了基于最优覆盖策略的2种移动信标路径规划方法。仿真结果表明,所提出的算法具有较高的定位精度,且所使用的移动路径性能较高。     

基于蒙特卡罗的无线传感器网络中的移动节点定位算法

针对信标节点固定、待定位节点移动的应用场景,在传统MCB算法的基础上,文章提出一种改进的蒙特卡罗盒子定位算法。该算法利用节点的历史估算位置,构建节点运动模型,采用灰色预测理论预测待定位节点可能到达的区域;并利用待定位节点与邻居信标节点以及非邻居信标节点的相对位置信息定义扩展锚箱,增加过滤条件,提高样本有效性,从而提高定位精度。仿真结果表明,改进方案在不同的信标节点密度、不同的节点运动速度等情况下,均表现出良好的性能。     

一种改进的迭代加权质心算法

提出了一种改进的迭代加权质心算法。主要通过改进传统质心定位算法中对信标节点范围的选取标准,并且为不同信标节点根据与未知节点的距离设定不同权值,通过迭代对周围信标节点较少的未知节点辅助定位进行改进。通过实验仿真验证了改进算法的有效性。     

基于加权最小二乘变尺度法的无线传感器网络定位

为了降低整个无线传感器网络的成本和减小测量误差对定位精度的影响,一般传统做法是把已定位的未知节点升级为信标节点,再对其他节点进行定位,但此情况会造成累积误差。为了减少累积误差,提出了一种加权的最小二乘变尺度定位算法,该算法首先利用加权最小二乘法对未知节点进行位置估计,然后把定位的未知节点升级为信标节点,再对剩下的未知节点进行位置估计,最后利用拟牛顿法对估计出来的位置进行优化。仿真结果表明,该算法能有效地减少测距误差和累积误差,降低网络成本,提高网络覆盖率和传感节点的定位精度,并且该算法不增加额外硬件设备,易于实现。     

一种无线传感器网络中 DV-Hop定位的改进算法

针对无线传感器网络中经典定位算法 DV-Hop 存在定位精度低的缺陷,提出了一种改进算法。在传统 DV-Hop 算法的基础上,首先采用最小均方误差准则校正信标节点的平均每跳距离,然后对各未知节点到参考信标节点的平均每跳距离进行加权处理,最后通过参数分析,对未知节点进行位置修正。仿真实验结果表明,改进算法相比于传统的 DV-Hop 定位算法以及已有的改进算法具有很高的定位精度,并且无需增加额外的硬件设施。因此在工程上具有很好的实用性。     

移动无线传感器网络定位算法研究

为了解决移动无线传感器网络中节点的自身定位问题,提出了一种基于运动预测的定位算法。该算法利用节点运动的连续性和接收信号强度测距方式,保存其最近两组历史位置信息,并结合节点当前的状态来估计自身位置。它不需要额外的硬件支持与较高的信标节点密度,满足复杂传输环境的应用要求。仿真结果表明,该算法具有较好的鲁棒性和较高的定位精度,节点随机运动时的定位误差约为15%,而直线运动时只有12%。     

无线传感器网络中基于RSSI的质心定位算法研究

无线传感器网络中,由于传统质心算法普遍存在信标节点分布不均与中心化问题,导致定位误差相对较大。针对这些问题,提出了基于RSSI的改进算法。在APIT的基础上,改进算法依靠未知节点接收到不同信标节点的RSSI数值,判断其周围是否存在最佳三角形,若存在则利用最佳三角形进行定位;若不存在则选出一个距其较近的三角形,利用移动信标节点的办法来缩小此三角形的范围进行定位。Matlab平台仿真结果表明,与传统质心算法相比,改进算法减少了定位误差,节点定位精度有所提高。     

DV-Hop节点定位算法研究与改进

在节点随机分布的无线传感器网络中,DV-Hop定位算法存在较大的误差。针对DVHop在智能停车场中定位精度不足的缺点,通过研究信标节点间估计距离和真实距离的误差,提出了改进的算法。改进后的算法修改了网络的平均跳段距离和未知节点坐标的估计范围,并用双曲线法取代了三边定位法,采用Max方法布置信标节点,克服了原算法在智能停车场定位中误差较大的缺点。     

An analytical geometric range free localization scheme based on mobile beacon points in wireless sensor network

In many applications of wireless sensor network, the position of the sensor node is useful to identify the actuating response of the environment. The main idea of the proposed localization scheme is similar with most of the existing localization schemes, where a mobile beacon with global positioning system broadcast its current location coordinate periodically. The received information of the coordinates help other unknown nodes to localize themselves. In this paper, we proposed a localization scheme using mobile beacon points based on analytical geometry. Sensor node initially choose two distant beacon points, in-order to minimize its residence area. Later using the residence area, sensor node approximate the radius and half length of the chord with reference to one of the distant beacon point. Then the radius and half length of the chord are used to estimate the sagitta of an arc. Later, sensor node estimate its position using radius, half length of the chord, and sagitta of an arc. Simulation result shows the performance evaluation of our proposed scheme on various trajectories of mobile beacon such as CIRCLE, SPIRAL, S-CURVE, and HILBERT.     

Movement-based location update and selective paging for PCSnetworks

This paper introduces a mobility tracking mechanism that combines a movement-based location update policy with a selective paging scheme. Movement-based location update is selected for its simplicity. It does not require each mobile terminal to store information about the arrangement and the distance relationship of all cells. In fact, each mobile terminal only keeps a counter of the number of cells visited. A location update is performed when this counter exceeds a predefined threshold value. This scheme allows the dynamic selection of the movement threshold on a per-user basis. This is desirable as different users may have very different mobility patterns. Selective paging reduces the cost for locating a mobile terminal in the expense of an increase in the paging delay. We propose a selective paging scheme which significantly decreases the location tracking cost under a small increase in the allowable paging delay. We introduce an analytical model for the proposed location tracking mechanism which captures the mobility and the incoming call arrival patterns of each mobile terminal. Analytical results are provided to demonstrate the cost-effectiveness of the proposed scheme under various parameters     

基于EKF的无线传感器网络移动信标定位算法

针对无线传感器网络节点定位精度较低的问题,提出一种基于扩展卡尔曼滤波的移动信标节点定位算法。该算法采用等距三重优化覆盖思想确定虚拟信标分布,利用蚁群算法获取最优遍历路径,同时引入扩展卡尔曼滤波算法以提高节点定位精度。通过对节点通信半径、虚拟信标数目、路径长度、迭代次数等参数分别进行仿真验证,结果表明本文算法定位精度明显优于普通质心定位算法,同时该算法在提高网络覆盖度、降低网络成本等方面也有较大优势。     

基于位置感知和代理的WSN多径路由方案

针对无线传感器网络(WSN)中多径路由的可靠性和能量效率问题,提出了一种基于代理和位置感知的多径路由发现方案(LABMR).事件节点根据位置信息,动态寻找其到Sink节点之间的特殊中间节点,来构建多径路由.利用移动代理来收集多径路由的局部拓扑结构信息,Sink节点根据代理收集的路由参数来计算路径权值,以此选择最优不相交路径.同时,对于信息的重要性差异,Sink节点选择单条或多条路径来传输数据,在保证传输可靠性的同时减少能耗.与现有的基于代理的多径路由(ABMR)方法相比,LABMP在数据包投递率、能量消耗、额外开销和延迟方面具有更好的性能.     

传感网络中基于移动信标的网格扫描定位算法

节点定位是传感网络最基本的技术之一,对此提出一种基于移动信标的网格扫描定位算法(Mobile Beacon Grid-Scan,MBGS)。该算法在网格扫描定位算法基础上,利用一个移动信标巡航整个传感区域,产生大量的虚拟信标,提高网络信标覆盖率,然后普通节点利用这些信标信息减小其可能区域(Estimative Rectangle,ER),并把新可能区域网格坐标质心作为其最新估计坐标。仿真结果表明,与Bounding Box、质心定位算法以及传统的网格扫描定位算法相比,MBGS定位方法的定位精度更高,算法性能更加稳定。     

High-accuracy and low-cost localisation scheme for wireless sensor networks

Recently, wireless sensor networks have been used in many promising applications including military surveillance, wildlife tracking, habitat monitoring and so on. They are an indispensable requirement for a sensor node to be able to find its own location. Many range-free estimate approaches eliminate the need of high-cost specialised hardware, at the cost of a less accurate localisation. In addition, the radio propagation characteristics vary over time and are environment dependent, thus imposing high calibration costs for the range-free localisation schemes. In order to reconcile the need for the high accuracy in location estimation, we describe, design, implement and evaluate a novel localisation scheme called laser beam scan localisation (BLS) by combining grid and light (laser) with mobile localisation policy for wireless sensor networks. The scheme utilises a moving location assistant (LA) with a laser beam, through which the deployed area is scanned and Zigbee platform is adopted for experiments in this article. The LA sends IDs to unknown nodes to obtain the locations of sensor nodes. High localisation accuracy can be achieved without the aid of expensive hardware on the sensor nodes, as required by other localisation systems. The scheme yields significant benefits compared with other localisation methods. First, BLS is a distributed and localised scheme, and the LA broadcasts IDs while unknown nodes listen passively. No interactive intersensor communications are involved in this process; thus, sensor energy is saved. Second, BLS reaches a sub-metre localisation error. Third, because the equation is simple, computational cost is low. Finally, BLS is a low-cost scheme because it does not require any infrastructure or additional hardware for sensor nodes.     

一种基于网络密度分簇的移动信标辅助定位方法

现有移动信标辅助定位算法未充分利用网络节点分布信息,存在移动路径过长及信标利用率较低等问题。该文把网络节点分簇、增量定位与移动信标辅助相结合,提出了一种基于网络密度分簇的移动信标辅助定位算法(MBL(ndc))。该算法选择核心密度较大的节点作簇头,采用基于密度可达性的分簇机制把整个网络划分为多个簇内密度相等的簇,并联合使用基于遗传算法的簇头全局路径规划和基于正六边形的簇内局部路径规划方法,得到信标的优化移动路径。当簇头及附近节点完成定位后,升级为信标,采用增量定位方式参与网络其它节点的定位。仿真结果表明,该算法定位精度与基于HILBERT路径的移动信标辅助定位算法相当,而路径长度不到后者的50％。     

One-step pointer forwarding strategy for location tracking indistributed HLR environment

One of the main challenges in personal communication service (PCS) is to locate many mobiles that may move frequently from place to place. Such a system operation is called location tracking. Many network signals flow, and database queries are required to achieve such a task. In addition to the two-level hierarchical strategy in IS-41 and GSM, several strategies have been proposed to improve the efficiency of location tracking. Pointer forwarding was used to reduce the expensive home location register (HLR) accesses. Previously, the distributed HLR scheme was proposed to prevent the HLR from becoming a bottleneck in the signaling network. However, the length of a forwarding pointer chain may be lengthened in a distributed HLR environment. We propose a more efficient strategy to overcome this potential problem. This strategy attempts to migrate the locating chains in a distributed HLR system when a mobile issues a registration operation. As a consequence, the length of any forwarding pointer chain does not exceed one in our strategy. Simulation results indicate that our strategy significantly decreases the locating cost. In fact, this strategy provides an upper bound of location tracking time owing to the fact that the length of any locating path does not exceed one. Furthermore, obsolete entries in local databases visitor location registers can be reclaimed in this strategy     

Distributed localization using mobile beacons in wireless sensor networks

A new distributed node localization algorithm named mobile beacons-improved particle filter (MB-IPF) was proposed. In the algorithm, the mobile nodes equipped with globe position system (GPS) move around in the wireless sensor network (WSN) field based on the Gauss-Markov mobility model, and periodically broadcast the beacon messages. Each unknown node estimates its location in a fully distributed mode based on the received mobile beacons. The localization algorithm is based on the IPF and several refinements, including the proposed weighted centroid algorithm, the residual resampling algorithm, and the markov chain monte carlo (MCMC) method etc., which were also introduced for performance improvement. The simulation results show that our proposed algorithm is efficient for most applications.