【作者】 诸燕平；

【导师】 谢求成；

【作者基本信息】 南京航空航天大学 ， 信号与信息处理， 2009， 博士

【摘要】 近年来,微机电系统、无线通信和数字电子技术的进步促进了具有低功耗、低代价与多功能特点的微型传感器制造技术的发展。大量具有传感单元、数据处理单元和通信单元的传感器节点引发了无线传感器网络的概念,即将大量的传感器密集地散布在感知区域,传感器间以自组织的方式构成无线通信网络,有效实现远程信息的采集、处理和传输。无线传感器网络受到国际学术界和工业界广泛关注,在工业、军事、环境等诸多领域具有广泛的应用前景。传感器节点自身定位是无线传感器网络的关键支撑技术。在传感器自身节点位置信息未知的情况下,无线传感器网络无法充分发挥其作用。因此,开发高效快捷的定位方法是无线传感器网络的基础理论和应用研究中一个重要的部分。本文紧跟国外最新研究发展方向,针对无线传感器网络自组织、低功耗、高冗余、短距离和布网灵活等特点,设计了新的定位算法,以实现在现有无线传感器网络节点配置下,提高无线传感器网络自身节点定位精度的目标。本文围绕无线传感器网络自身节点定位提高精度、减少计算开销和增强算法可扩展性的需求,对国内同类较少研究的节点间协作定位算法展开研究。本文中所提出的定位算法采用凸优化理论,这种思路和方法在国内尚属首次,具有较好的理论意义和工程实用前景。本文的主要研究内容为:首先,研究了各种无线传感器网络节点定位算法,例如极大似然估计、基于泰勒分解的最小二乘法、总体最小二乘法,以及近年来提出基于半定规划的定位算法等。通过算法分析和仿真实验,指出了各算法的优劣点。其次,本文将凸优化理论应用于无线传感器网络节点定位问题上。针对半定规划的无线传感器网络定位算法的不足之处,提出了新的基于线性和二次规划的无线传感器网络定位算法,并对同时使用距离和角度信息及仅使用角度信息的两种定位算法分别进行了数学推导、理论分析和仿真实验。对于相同规模的线性规划、二次规划和半定规划问题,线性规划和二次规划问题的计算复杂度要远远低于半定规划问题的计算复杂度。总体上说,在保证定位精度不变的前提下,本文提出的定位算法具有更小的计算复杂度,因此更加适用于解决实际的定位问题。实验结果表明,与基于半定规划的定位算法相比,新算法可以有效的减少运算开销、提高节点定位精度,并且降低了定位精度对锚节点部署的依赖程度。再次,为了进一步提高算法精度,对定位误差进行极小极大优化处理,从而有效降低定位算法的最坏情况误差。仿真实验证明,在满足了节点定位算法整体性能的同时,极小极大优化定位算法能有效地降低单个节点的最坏情况定位误差。最后,针对无人机定位中GPS无法正常工作的考虑,提出了应用无线传感器网络定位作为无人机辅助定位方式的新思路,以及无人机作为无线传感器网络中继的新想法。对无人机导航定位系统的多元化发展提出了创建性的意见,并对实现方式作出了前瞻性的研究,具有重要参考价值。本文中所提出的定位算法均在Matlab平台上进行了仿真验证,给出了相应的性能分析。更多还原

【Abstract】 Advances in micro-electro-mechanical system (MEMS) technology, wireless communications and digital electronics have enabled the development of low-cost, low-power, multifunctional sensor nodes that are small in size and communicate untethered in short distances recently.These tiny sensor nodes which consist of sensing, data processing, and communicaiting components, leverage the idea of wireless sensor networks (WSNs) based on collaborative effort of a large number of nodes. WSNs have extensively drawn academic and industrial attention. WSNs have a variety of applications in the aspects of industry, military, and environment. Sensor localization is one of important supporting techniques of WSNs. When sensors’locations are unknown, WSNs cannot play roles in practical applications. Therefore, it is an important part of research of WSNs to develop efficient and expeditious localization methods.The work reported in this dissertation follows active international research directions. Based on the properties of WSNs, e.g., self-organization, low-power consumption, high redundancy, short distance, and flexible network distribution, new localization methods for WSN are proposed in this dissertation, through which the localization accuracy can be improved without changing the sensor configuration of WSNs. In order to increase the localization accuracy, decrease the computational cost, and improve the scalability of localization methods, this dissertation focuses on collaborative localization methods, which are seldom studied currently in China. The proposed localization methods are based on convex optimization. This design strategy is first employed in China. Thus, the proposed methods are of profound significance in both theoretical study and practical application.The dissertation is organized as follows:Firstly, we study various existing localization methods, such as maximum likelihood estimation, Taylor least-squares method, total least-squares method, and newly proposed semi-definite programming (SDP) method. Through algorithmic analysis and simulation experiments, the advantages and disadvantages of these existing methods are pointed out.Secondly, convex optimization is employed to resolve sensor localization problems of WSNs. As an attempt to overcome the disadvantage of the SDP-based localization method, novel methods based on linear programming (LP) and quadratic programming (QP) are proposed in this dissertation. For the localization methods of using distance-angle and pure angle measurements, mathematical derivations, theoretical analysis, and simulation experiments are conducted, respectively. Simulation results illustrate that compared with SDP-based method, the proposed localization methods can effectively reduce the computational cost, improve the localization accuracy, and decrease the dependence on the distribution of anchor nodes.Thirdly, as an attempt to improve the localization accuracy, a minimax optimization strategy is employ to further reduce the worst-case localization error. Simulation results show that the worst-case localization error for each unknown sensor can be effectively reduced, as well as the overall performance of the localization method is unaffected.At last, upon the consideration that GPS cannot be utilized in localization of unmanned aerial vehicle (UAV), a new strategy is proposed to apply sensor localization technique as a complement means in UAV localization. Furthermore, a novel thought of using UAV as a relay station of WSNs is proposed in this dissertation. Some innovative ideas on the diverse development of navigation and positioning system of UAV are also discussed in this dissertation. Some prospective studies regarding the implementation issues are made in this dissertation. All of these are of especial importance.All the localization methods proposed in this dissertation have been verified through simulation experiments on Matlab platform. The corresponding performance analysis is also carried out.更多还原