【作者】 翁志远；

【导师】 葛建华； 钱良； 杨峰；

【作者基本信息】 上海交通大学 ， 通信与信息系统， 2010， 硕士

【摘要】 在无线传感网络中,位置信息对传感器网络的监测应用非常重要,事件发生的位置或获取信息节点的位置是传感器节点监测内容中所包含的重要信息,没有位置信息的监测消息往往毫无意义。因此,对无线传感网络节点的定位成了当前无线传感网络研究领域的热点问题,解决该问题对无线传感网络的广泛应用具有重要意义。本文根据当前无线传感网的应用特点,对基于到达时间(TOA)测距方法的协作定位问题进行了研究。无线传感网的协作定位精度和许多因素有关。本文把Cramer-Rao定理中的FIM矩阵作为分析工具,分析了在协作定位中,影响定位精度的各种因素。同时本文还从理论上证明了协作定位相对于非协作定位一定可以带来定位精度的提高。针对无线传感网的协作定位问题,本文提出了一种分布式,高精度,低复杂度的定位算法。算法首先利用DV-hop算法的思想,通过计算到基站的跳数来估计节点的初始位置,在得到一个较好的初始位置后,开始迭代计算最优解。算法根据每个节点的CRLB和到最近基站的跳数赋予每个节点一个权重值。在计算非线性最小二乘法时,权重值越大,则该项误差将被优先最小化。仿真结果表明该算法有快速的收敛性,该算法的综合性能优于当前最好的集中式算法SDP。更多还原

【Abstract】 Location information is critical to the surveillance of the network in wireless sensor network. The location of the event or the location of the node from which information is acquired are important information in sensor network monitoring. Monitoring without location information is usually meaningless. Therefore, estimating the location of the event or the location of the node is the fundamental function of WSN. The problem of locating nodes in sensor network has become a hot issue. TOA-based cooperative localization technique has been investigated in this work.In WSN, the accuracy of cooperative localization is related to many factors. In this work, Fisher Information Matrix in Cramer-Rao Lower Bound has been used as tool for analysis. Several factors related to accuracy are analyzed. In addition, the benefit from cooperative localization compared with non-cooperative localization is proved.A novel distributed, high-accurate and low complexity localization algorithm is proposed. Firstly, the thought from DV-hop is employed. By counting hop from mobile node to fixed node, approximate distance can be estimated. After distances to all fixed node are estimated, the approximate location can be calculated, which is a good initial value for iterative method. Then every node is assigned a weight value according to their CRLB and hop counts to nearest fixed node. When solving nonlinear least square, the item with the largest weight will have the highest priority to have its error minimized. Simulation shows that the algorithm converges quickly, and global optimum solution is guaranteed. In general situation, the proposed algorithm performs better than currently best SDP method.更多还原