【摘要】：隨著全球衛(wèi)星導(dǎo)航系統(tǒng)室內(nèi)定位軟肋的日益凸顯,加之定位系統(tǒng)與通信技術(shù)的緊密結(jié)合,室內(nèi)定位拓寬了個(gè)人用戶位置信息的應(yīng)用范圍,展現(xiàn)出了更多的應(yīng)用前景和實(shí)際需求。近年來(lái)隨著無(wú)線傳感器網(wǎng)絡(luò)(Wireless Sensor Network,WSN)應(yīng)用的普及,除了獲取節(jié)點(diǎn)必要的感知數(shù)據(jù)以外,探知數(shù)據(jù)來(lái)源,明確節(jié)點(diǎn)位置和指定事件發(fā)生地點(diǎn)也成了WSN的重要功能之一。因此,利用WSN自身特點(diǎn),在不增加成本投入前提下,完成節(jié)點(diǎn)室內(nèi)定位功能,拓展WSN的應(yīng)用方向,具有重要的應(yīng)用研究?jī)r(jià)值和廣闊的發(fā)展空間。文中首先給出了一種適合在WSN中基于接收信號(hào)強(qiáng)度指示(Receive Signal Strength Indication,RSSI)應(yīng)用的極大似然估計(jì)直接求解定位算法。考慮窄帶無(wú)線信號(hào)的路徑損耗和陰影衰落,直接建立多個(gè)參考節(jié)點(diǎn)的RSSI值與待定位目標(biāo)節(jié)點(diǎn)坐標(biāo)之間的解析關(guān)系,避開傳統(tǒng)RSSI定位方法中常用的對(duì)收發(fā)節(jié)點(diǎn)之間距離量的直接求解,減少測(cè)距誤差,提高定了位精度。并通過(guò)數(shù)值仿真分析了參考節(jié)點(diǎn)數(shù)量、遮擋因子、路徑損耗指數(shù)等因素對(duì)定位精度的影響。文中采用Zig Bee技術(shù)下CC2530無(wú)線射頻芯片實(shí)現(xiàn)了基于RSSI的WSN定位系統(tǒng)。詳細(xì)給出了WSN中定位節(jié)點(diǎn)的硬件設(shè)計(jì)過(guò)程、片上程序開發(fā)流程和計(jì)算機(jī)監(jiān)控界面的設(shè)計(jì)方法。通過(guò)間接提高RSSI值的精度、設(shè)定接收RSSI值的閾值、使用計(jì)時(shí)器保證RSSI值的可靠性、優(yōu)化Z-Stack協(xié)議棧等多種方法,從系統(tǒng)設(shè)計(jì)的角度上進(jìn)一步降低了定位誤差。最后給出了定位系統(tǒng)的實(shí)測(cè)分析,以驗(yàn)證系統(tǒng)在算法、軟硬件設(shè)計(jì)上的合理性。與現(xiàn)有建立非線性方程組求解定位坐標(biāo)的極大似然估計(jì)定位算法相比,使用本文定位算法設(shè)計(jì)實(shí)現(xiàn)的定位系統(tǒng),提高定位點(diǎn)穩(wěn)定度的同時(shí),在相同定位準(zhǔn)確度的情況下,可以明顯降低定位誤差。8個(gè)參考點(diǎn)對(duì)m4m4?正方形區(qū)域定位,其誤差可降至0.36m,16個(gè)參考點(diǎn)對(duì)m10m10?定位區(qū)域定位,誤差約為0.97m。此外,以本套定位系統(tǒng)為平臺(tái),本文還實(shí)測(cè)分析給出了,增加定位區(qū)域內(nèi)參考節(jié)點(diǎn)數(shù)量、設(shè)置合適的RSSI接收閾值、參考節(jié)點(diǎn)角度均勻圍繞未知節(jié)點(diǎn)擺放等,都可在一定程度上提升定位精度的結(jié)論。
[Abstract]:With the increasingly prominent weakness of indoor positioning of global satellite navigation system and the close combination of positioning system and communication technology, indoor positioning widens the application scope of personal user location information, and shows more application prospects and practical needs. In recent years, with the popularity of wireless sensor network (Wireless Sensor Network,WSN) applications, in addition to acquiring the necessary perceptual data of nodes, finding out the source of data, determining the location of nodes and specifying the location of events have become one of the important functions of WSN. Therefore, using the characteristics of WSN, without increasing the cost input, to complete the node indoor positioning function, expand the application direction of WSN, has important application research value and broad development space. In this paper, a direct location algorithm based on maximum likelihood estimation based on received signal strength indicator (Receive Signal Strength Indication,RSSI) in WSN is presented. Considering the path loss and shadow fading of narrowband wireless signals, the analytic relationship between the RSSI values of multiple reference nodes and the coordinates of the target nodes to be located is established directly. In order to avoid the direct solution of distance between transceiver nodes, which is commonly used in traditional RSSI positioning methods, the ranging error is reduced, and the positioning accuracy is improved. The effects of the number of reference nodes, occlusion factor and path loss index on the positioning accuracy are analyzed by numerical simulation. In this paper, CC2530 radio frequency chip based on Zig Bee technology is used to realize WSN positioning system based on RSSI. The hardware design process, on-chip program development flow and the design method of computer monitor interface in WSN are presented in detail. By indirectly improving the precision of RSSI value, setting the threshold of receiving RSSI value, using timer to ensure the reliability of RSSI value and optimizing the Z-Stack protocol stack, the positioning error is further reduced from the point of view of system design. Finally, the actual measurement analysis of the positioning system is given to verify the rationality of the algorithm, software and hardware design of the system. Compared with the existing maximum likelihood estimation (MLE) localization algorithms for solving the location coordinates by establishing nonlinear equations, the positioning system designed by this method can improve the stability of the positioning points, and at the same time, the location accuracy is the same. The positioning error can be significantly reduced. 8 reference points are m4m4? The error of square region positioning can be reduced to 0.36 m, 16 reference points to m 10? The error is about 0.97 m. In addition, on the platform of the system, the paper also gives the following analysis: increasing the number of reference nodes in the location area, setting appropriate RSSI reception threshold, and placing the reference node angle evenly around the unknown node, etc. Can improve the accuracy of positioning to a certain extent.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN929.5;TP212.9

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本文編號(hào)：2370147