无线网络定位综述

A Survey on Localization Model in Wireless Networks

结合无线网络技术,从无线网络定位数学模型的角度对定位问题进行了统一的形式化描述,该描述涵盖测量与距离估算技术、二维空间或多维空间中的定位映射关系以及绝对定位和相对定位的定位需求;论文由模型映射关系是否存在的问题引出了无线网络定位的可行性问题,以唯一实现理论以及刚性图理论作为无线网络定位的可行性模型并对其进行了分析总结;在数据层面对定位系统的测量技术以及信息采集技术进行了分析,将距离测量技术,角度测量技术以及距离估算技术从数学模型角度统一为有用信息采集,并将能用于定位的信息涵盖进来,以此作为定位模型优化与扩展的基础;单目标网络的定位算法较多,但其数学本质上是对同一类目标函数不同的求解方法,该文从数学模型及其优化方法的角度对其进行了分析,总结了不同解法的相似效果;与单目标网络定位不同,多目标网络定位问题虽然定位模型统一,但其求解方法却不尽相同,该文对半定规划方法、多维标度方法以及非线性映射曲元分析方法进行了总结;在对数据采集技术,定位方法进行了总结后,该文系统分析了信息集合对定位算法的影响,从功能上将各种定位技术分为信息采集技术、定位可行性理论、定位模型以及定位优化技术,提出了系统设计层面定位性能提高的主要设计思路,从定位方案的选取上将优化技术看成定位系统中的可选项,基于定位优化技术的相对独立性,提出了定位方案的分治策略;随后该文对定位评估指标中的误差指标和统计学指标进行了总结,以此作为定位性能评估的主要手段;最后提出了无线网络定位领域理论及技术所面临的问题与挑战.

In this paper we discuss the models of localization in wireless networks with the use of wireless technologies.A universal formal description of wireless localization is proposed from the standpoint of mathematical models,which can cover the technologies of ranging measurement and ranging estimation,the mapping function from original data to localization result in 2dimensional or multi-dimensional space,and relative localization or absolute localization. Whether the mapping function of the formal description exists or not means the feasibility of wireless localization,and this is the problem of unique realization or the rigid graph,so we give a deep analysis and summary of the unique realization doctrine and the rigid graph doctrine afterwards and point out that these two doctrines are in fact the same in describing localization feasibility problem.Then,from mathematical standpoint,various information collecting techniques are summarized as working information collecting in mathematical models,which includes distance ranging technologies such as TDoA,angle measuring technologies（AoA）and distance estimating technologies.The description of working information collecting can cover other information that can be used to dothe localization and can be viewed as the basis to carry out optimization or extension for wireless localization.After that,we focus on single-target localization model in wireless networks.Although various solutions for single-target localization are proposed,they all comply with the same localization model,which has more than n＋1beacons in n dimensional space and only one to-be-located node.We summarize the solutions of single-target localization and point out that some of the solutions are nearly the same essentially.Unlike single-target localization,there are various different solutions for multi-target localization.We summarize the methods of Semidefinite Programs,Multidimensional Scaling and Curvilinear Component Analysis.Then the impact of working information set for wireless localization is analyzed,which can provide ideas to optimize localization performance in the systematic level.In the aspect of functionality,various localization technologies can be classified into information collecting technology,feasibility theory of localization,localization model and localization optimizing technology.With these technologies we give a system designing suggestion for localization performance in the systematic view.We can do the localization in a divide-and-conquer manner because some localization technologies are independent to each other.Subsequently,we summarize the assessing criterions for wireless localization including the definition of precision and accuracy,Cramer Rao bound,Circular Error Probability（CEP）,Dilution of Precision（DOP）and finally we state the problems and challenges with new rapidly growing requirements.