面向无线多媒体传感网实时定位的信道传播模型研究及验证

The rapid development of Internet of Things(IOT) and mobile internet brings forward an impending requirement for wireless multimedia sensor networks (WMSN) high-precision real-time location method, while the establishment of wireless channel model is the key to achieve high-precision positioning method. However, due to the diversity and complexity of the WMSN deployment environment, there is great difficulty in establishing accurate radio channel propagation model. This study, with the electromagnetic wave propagation properties in complex environments as the research object, adopts the three-dimensional Finite-Difference Time-Domain (FDTD) algorithm and experimental measurement method study the electromagnetic wave propagation in real environments on the base of WMSN antenna radiation modeling and environmental parameters mathematical modeling, and explore quantitative functional relationship between various environmental factors with electromagnetic wave transmission loss and propagation path changing law, then combines theoretical analysis method and laboratory testing method design a sensible low-complexity wireless channel model and its algorithm, which extracting real environment information, for WMSN high-precision real-time positioning. The study will design a real-time angle of arrival(AOA)-received signal of strength (RSSI) based combining iterative location method based on the radio channel propagation model, and do experimental verification. The successful implementation of this project will provide a theoretical foundation and technical means for wireless sensor network high-precision positioning research and positioning system development in practical applications, which has important theoretical significance and engineering value.

物联网和移动互联网的迅速发展对无线多媒体传感网(WMSN)高精度实时定位提出了迫切的需求，而无线信道模型的建立是实现高精度定位方法的关键。但由于WMSN部署环境的多样性和复杂性，建立准确的信道传播模型存在不小的困难。本课题以复杂环境参数下的电磁波传播特性为研究对象，在研究并实现WMSN天线辐射模型和环境参数数学模型的基础上，利用三维时域有限差分算法仿真模拟结合实验测量方法对实际环境中的电磁波传播情况展开研究，探索不同环境因素与电磁波传输损耗间的定量关系及其传播路径改变规律，在理论分析和实验室试验的基础上设计一种能够真实反映环境参数的、面向WMSN高精度实时定位的、低复杂度的无线信道传播模型及其实现算法。本课题还将设计基于该信道模型的实时定位方法并进行实验验证。本项目的成功实施将为面向实际应用的WMSN高精度定位方法研究和定位系统研制提供理论基础和技术手段，具有重要的理论意义和工程应用价值。

基于RSSI测距的定位方法是无线传感网定位应用中的主流技术，但是面临诸多问题和挑战： 传统的质心定位算法需要三个以上的锚节点才可以完成定位，需要占用额外的无线信道；广泛应用的全向天线和板载天线辐射特性复杂，简单的辐射激励模型不再适用；无线信号强度在大尺度条件下受多种因素影响，信道传播模型建立困难等。. 本项目针对上述无线传感网实时定位算法中的关键理论，技术和问题进行了深入研究。首先，提出了一种无需锚节点间通讯的基于天线阵列的单锚节点定位方法和系统；研发了天线辐射特性自动测量系统实现天线辐射特性的快速自动测量和模型建立；设计并制作了适用于单锚节点定位的PCB定向天线，在对天线阵列的辐射特性进行仿真和测量的基础上进行天线结构优化得到具有优秀前后辐射抑制比的，规则方向性图的４天线天线阵列，并以此建立准确的激励源数学模型。设计了一种基于简单参数表的到达角度-信号强度结合的低复杂度的实时定位算法,实验证明能够达到1.01米的平均距离精度和20度的角度误差,仿真结果和实验结果都表明我们设计的算法是一种低复杂度、高效且精确的WSN单锚节点实时定位算法。同时在本课题研发了天线特性自动测量系统原型一套，基于天线阵列的单锚节点实时定位系统一套，这些研究成果将为无线传感网和物联网终端网络等近距离无线网络实时定位研究和应用提供新的思路。