节点文献
基于无线电和超声波的室内定位技术响应时间的研究
Research on Responding Time of Indoor Location Technique Based on Radio Frequency and Ultrasound
【作者】 韩刚；
【导师】 王鸿鹏；
【作者基本信息】 哈尔滨工业大学 ， 计算机科学与技术， 2009， 硕士
【摘要】 室外定位技术难以满足位置感知技术的需要,室内位置服务也变得越来越重要,室内环境下GPS等室外定位技术往往会不能正常工作,甚至彻底失效。因此室内位置服务存在大量应用需求,但是影响室内定位技术的因素多,室内定位技术特性复杂,因此室内定位技术是近年研究的难点和热点。本文针对室内定位技术的特点,查阅整理了室内无线-超声定位技术性相关文献,分析了典型系统设计思想和优缺点,在此基础上提出并设计了对基于无线电和超声波的无线传感器网络室内定位技术的典型系统——Cricket系统的响应时间方面的改进方案。Cricket室内定位系统的优点是具有私密性和对分散物体的可测量性(对待测节点数量没有限制),但是在响应时间方面存在一定缺点,由于其信标节点发射时间为随机发射(类似Aloha),出现冲突在所难免,因此存在响应时间较长且不稳定(实施性差)的缺点。本文介绍了一种通过引入中心控制来协同调度各个信标节点的发射时间,从而达到信标节点依次发射(类似TDM),从而对信标节点实现冲突避免和缩短发射间隔进而实现整体系统的响应时间缩短和系统响应时间的稳定(实时)化的改进方案,并且介绍了对该改进方案进行评估实验的方法以及实验结果,结果表明该系统在保证不破坏Cricket室内定位系统私密性、待测节点数量无限制特性以及较高的定位精度的前提下,能够有效缩短响应时间,并且减小响应时间的波动(改进实时性)。
【Abstract】 Outdoor positioning technology can’t meet the needs of location-aware technologies; indoor location/positioning services are becoming more and more important, in the indoor environments outdoor positioning technology such as GPS often doesn’t work well, or even completely unavailable. There is much requirement of indoor location-based services applications. However, the impact of indoor positioning technology factors, and characteristics of the complex, an indoor positioning technology is a difficulties and hot spots of recent study. In this paper, the characteristics of a indoor positioning technology which is a Radio frequency - ultrasound based wireless sensor network indoor positioning typical system - Cricket system, and the design and implement of it’s improvement on the response time.Cricket Indoor Location System has the advantage of privacy and did not limit the number of test nodes, but there is some disadvantage of response time. Because the beacon node has a policy of random beacon (similar to Aloha), there conflict is inevitable, so there is a longer response time and unstable (response time is not real time).In this paper, a central control architecture is introduced, this architecture will coordinate the beacon of beacon node to avoid conflict and reduce the beacon interval to achieve the overall system response time to be shorter and more stable(real time).And also the experimental method and experimental results show that the system not to undermine the Cricket Indoor Location System privacy, unlimited number of properties of test nodes, positioning accuracy of the premise, can effectively shorten the response time and make response time stable (real time).