Path planning using a mobile anchor node based on trilateration in wireless sensor networks

In wireless sensor networks (WSNs), many applications require sensor nodes to obtain their locations. Now, the main idea in most existing localization algorithms has been that a mobile anchor node (e.g., global positioning system‐equipped nodes) broadcasts its coordinates to help other unknown nodes to localize themselves while moving according to a specified trajectory. This method not only reduces the cost of WSNs but also gets high localization accuracy. In this case, a basic problem is that the path planning of the mobile anchor node should move along the trajectory to minimize the localization error and to localize the unknown nodes. In this paper, we propose a Localization algorithm with a Mobile Anchor node based on Trilateration (LMAT) in WSNs. LMAT algorithm uses a mobile anchor node to move according to trilateration trajectory in deployment area and broadcasts its current position periodically. Simulation results show that the performance of our LMAT algorithm is better than that of other similar algorithms. Copyright © 2011 John Wiley & Sons, Ltd.     

WSN中基于RSSI的加权质心定位算法的改进

自身节点定位是无线传感器网络的关键技术之一。本文对距离无关定位算法中的质心定位算法进行了分析,在基于RSSI的质心定位算法的基础上提出了一种新的校正RSSI测距值的加权定位算法。测距阶段将信标节点之间的距离和信号强度信息同时考虑在内进行RSSI值校正,权值选择阶段采用了修正传统权重的计算方法,权值取距离倒数之和。通过仿真证明,本文提出的算法相对于传统的加权质心定位算法有明显改进,获得较好的定位精度。     

Moving anchor node localization algorithm based on network connectivity

In order to better solve the contradiction between precision of localization and the number of anchor nodes in wireless sensor network,a mobile anchor node localization technology based on connectivity was proposed.First,the coverage characteristic of the network nodes was analyzed,and a critical value was found between the mobile step and the anchor node communication radius,mobile anchor nodes＇ coverage characteristic would change when near this critical value.Second,a mobile anchor node followed a planning path to form a positioning area seamless coverage was used.Finally,when there was no need for high-precision technology,node position would been estimated according with the connectivity of the network and the receiving information of the node.The simulation results show that the proposed algorithm can realize coarse-grained localization,and paths perform complete localization.     

Research on mobile strategy of anchor node based on weighted virtual force model

The existing mobility strategy of the anchor node in wireless sensor network (WSN) has the shortcomings of too long moving path and low positioning accuracy when the anchor node traverses the network voids area.A new mobility strategy of WSN anchor node was proposed based on an improved virtual forces model.The number of neighbor nodes and the distance between the neighbor nodes to the anchor nodes were introduced as their own dense weight attributes.The unknown nodes intensity was used as weights to improve the traditional virtual force model.Meantime the distance-measuring error ε was taken into account.The optimal distribution,direction selection,shift step length and fallback strategy of anchor node could be analyzed by the trilateration.Using the number of virtual beacon received by the unknown node and the distance between the unknown node to the anchor node calculate the virtual force.Then according to the virtual force,the direction was chosen and the anchor nodes were moved.Simulation experiments show that the strategy can make the anchor nodes move according to the specific circumstances of unknown node distribution.It has a high positioning accuracy and strong adaptability.It can successfully shorten the path of the anchor node movement and reduce the number of virtual beacon.Moreover it can effectively avoid the anchor node to enter the network voids area and reduce the number of collinear virtual anchor nodes.     

A mobile sink path planning for wireless sensor networks based on priority‐ordered dependent nonparametric trees

The professional design of the routing protocols with mobile sink(s) in wireless sensor networks (WSNs) is important for many purposes such as maximizing energy efficiency, increasing network life, and evenly distributing load balance across the network. Moreover, mobile sinks ought to first collect data from nodes which have very important and dense data so that packet collision and loss can be prevented at an advanced level. For these purposes, the present paper proposes a new mobile path planning protocol by introducing priority‐ordered dependent nonparametric trees (PoDNTs) for WSNs. Unlike traditional clustered or swarm intelligence topology‐based routing methods, a topology which has hierarchical and dependent infinite tree structure provides a robust link connection between nodes, making it easier to reselect ancestor nodes (ANs). The proposed priority‐ordered infinite trees are sampled in the specific time frames by introducing new equations and hierarchically associated with their child nodes starting from the root node. Hence, the nodes with the highest priority and energy that belong to the constructed tree family are selected as ANs with an opportunistic approach. A mobile sink simply visits these ANs to acquire data from all nodes in the network and return to where it started. As a result, the route traveled is assigned as the mobile path for the current round. We have performed comprehensive performance analysis to illustrate the effectiveness of the present study using NS‐2 simulation environment. The present routing protocol has achieved better results than the other algorithms over various performance metrics.     

Hybrid area exploration–based mobility‐assisted localization with sectored antenna in wireless sensor networks

In common practice, sensor nodes are randomly deployed in wireless sensor network (WSN); hence, location information of sensor node is crucial in WSN applications. Localization of sensor nodes performed using a fast area exploration mechanism facilitates precise location‐based sensing and communication. In the proposed localization scheme, the mobile anchor (MA) nodes integrated with localization and directional antenna modules are employed to assist in localizing the static nodes. The use of directional antennas evades trilateration or multilateration techniques for localizing static nodes thereby resulting in lower communication and computational overhead. To facilitate faster area coverage, in this paper, we propose a hybrid of max‐gain and cost‐utility–based frontier (HMF) area exploration method for MA node's mobility. The simulations for the proposed HMF area exploration–based localization scheme are carried out in the Cooja simulator. The paper also proposes additional enhancements to the Cooja simulator to provide directional and sectored antenna support. This additional support allows the user with the flexibility to feed radiation pattern of any antenna obtained either from simulated data of the antenna design simulator, ie, high frequency structure simulator (HFSS) or measured data of the vector network analyzer (VNA). The simulation results show that the proposed localization scheme exhibits minimal delay, energy consumption, and communication overhead compared with other area exploration–based localization schemes. The proof of concept for the proposed localization scheme is implemented using Berkeley motes and customized MA nodes mounted with indigenously designed radio frequency (RF) switch feed network and sectored antenna.     

基于二次质心的无线传感器网络定位算法

节点的定位是无线传感器网络中的一种重要技术。提出了一种新的无线传感器网络定位算法——基于二次质心算法的定位算法,与以往的基于三边测量的加权质心方法不同,该算法改进了对未知节点位置的估算方法,一定程度上避免了因多次估算质心而产生的累积误差,提高了定位精度。仿真表明,该算法的定位精度较之前的三边测量方法提高了约19%。     

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DV-HOP的改进算法及仿真

节点定位技术是无线传感器网络中的关键技术之一。为了提高节点定位精度,在DV-HOP算法的基础上提出两种改进措施:锚节点规划部署和加权算法,改进后的算法统称为加权DV-HOP。在新算法的基础上建立Matlab仿真模型。仿真结果表明加权DV-HOP算法,在相同的锚节点数量和锚节点无线覆盖范围下,节点定位精度约提高10%。     

无线传感器网络节点的三维质心定位算法研究

由于无线传感器网络中的节点初始位置并不固定,所以需要利用合理的定位算法进行无线传感器网络的节点位置的确定。而利用三维质心定位算法,可以通过假设锚节点和利用三维坐标系来进行曲面三维体的确定,从而将三维体的质心当做是未知节点进行位置的计算。因此,基于对这一算法的认识,本文对无线传感器网络节点的三维质心定位算法进行了研究,并对其性能进行了分析,从而为关注这一话题的人们提供参考。     

基于改进DV-Hop的无线传感器网络节点定位算法

针对DV-Hop距算法定位误差大的难题,提出一种改进离估计误差,并利用DV-Hop的传感器节点定位算法。首先修正知节点与信标节DV-Hop算法对节点进行定位;然后对进V-Hop算法定位误差行校正,最后在Matlab 2012平台上对算法性能进行仿真分析。仿真结果表明,本文算法可以较好地克服DV-Hop算法存在的不足,提高了传感器节点的定位精度。     

基于TinyOS的CC2430 RSSI定位的设计与实现

为解决现Z-Stack定位程序代码量大,结构复杂等问题,提出一种基于TinyOS的CC2430定位方案。在分析TinyOS组件架构基础上,设计实现盲节点、锚节点与汇聚节点间的无线通信以及汇聚节点与PC机的串口通信。在此基础上实现PC对各锚节点RSSI(Received Signal Strength Indicator)寄存器值的正确读取,确定实验室环境下对数-常态无线传播模型的具体参数,并采用质心算法来提高定位精度。实验显示,在由四个锚节点组成的4.8×3.6 m2矩形定位区域中,通过RSSI质心定位算法求得的盲节点坐标为(2.483 1,1.018 5),实际坐标为(2.40,1.20),误差为0.199 6 m,表明较好地实现对盲节点的定位。     

无线传感器网络节点定位技术

无线传感器网络（Wireless Sensor Network,WSN）在许多领域有广泛的应用,无线传感器网络中节点位置对无线传感器网络的应用有重要的影响,没有位置属性的信息是无价值的,定位技术是无线传感器网络的重要研究方向之一.依据测距和非测距的分类方法,介绍节点定位技术的基本原理和方法及当前的发展状况,最后对节点定位技术的发展方向作展望.     

基于序列的传感器网络节点定位算法

针对MSP算法需要借助额外的外部扫描设备,不适合应用于对野外大规模部署的传感器网络进行定位这一缺点,提出了一种HG-MSP算法。该算法通过锚节点发出扫描信息,不需要额外的外部设备进行辅助定位,提高了算法的可用性。仿真实验表明,在去掉辅助设备的情况下,算法的定位精度并无明显下降。     

Mobile anchor assisted particle swarm optimization (PSO) based localization algorithms for wireless sensor networks

Node localization is essential to wireless sensor networks (WSN) and its applications. In this paper, we propose a particle swarm optimization (PSO) based localization algorithm (PLA) for WSNs with one or more mobile anchors. In PLA, each mobile anchor broadcasts beacons periodically, and sensor nodes locate themselves upon the receipt of multiple such messages. PLA does not require anchors to move along an optimized or a pre‐determined path. This property makes it suitable for WSN applications in which data‐collection and network management are undertaken by mobile data sinks with known locations. To the best of our knowledge, this is the first time that PSO is used in range‐free localization in a WSN with mobile anchors. We further derive the upper bound on the localization error using Centroid method and PLA. Simulation results show that PLA can achieve high performance in various scenarios. Copyright © 2011 John Wiley & Sons, Ltd.     

盲区条件下一种基于记忆机制的移动机器人快速路径规划方法

如何在存在盲区的条件下实现机器人路径规划,是现实中的一大难点问题。本文利用路口点表征自由路径,通过估算盲区内路口点位置及其存在的概率,实现对历史感知数据的记忆与利用。建立评价函数对盲区内路口点及感知范围内的路口点进行评价,同时利用了历史感知信息与当前感知信息。与传统局部路径规划方法相比,该方法避免了盲区带来的徘徊、规划失败等问题。仿真表明了该方法的有效性。     

基于环境模型的移动机器人路径规划

介绍了一种新的移动机器人路径规划方法。采用链接图法,对工作空间建模。用Dijkstra算法决策出全局最短路径,然后用遗传算法对此路径进行优化,得到全局最优路径。最后提出了一种对路径几何改进的方法。仿真结果表明,该方法方便简单,对所规划的路径质量有所提高。     

移动机器人路径规划方法研究

移动机器人技术研究中的一个重要领域是路径规划技术，它分为基于模型的环境已知的全局路径规划和基于传感器的环境未知的局部路径规划。综述了移动机器人路径规划技术的发展现状指出了各种方法的优点与不足，最后对移动机器人路径规划技术的发展趋势进行了展望。     

一种面向无线传感器网络的分布式定位算法

针对无线传感器网络(WSN)的水下应用,在原有同类算法研究的基础上,提出了一种分布式无信标节点的相对定位算法。该算法结合了最高节点度分簇算法和经典度量多维尺度定位的理论。理论分析和仿真实验表明,与SDGPSN定位算法相比,该定位算法提高了约10%的定位精度。     

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。