隨機分布無線感測器網路節點並自行定位之研究

Relative-Localization Identification of Random Distributed Wireless Sensor Network Nodes

魏瀅峰(Ying-Feng Wei)

指導教授 ： 吳文中

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.02820

摘要

近年來，定位一直是多項應用科技所渴望的技術。由於監測環境大小不一，不可避免地需要佈置多個感測器節點，並將訊息以路由的方式漸漸傳到資料蒐集的位置，無線感測器網路對於上述的要求是一項非常好的選擇。然而過去的無線感測器網路定位系統多半需要事先裝設位置已知的節點當作參考點來定出其他待測節點的位置，而此類系統架設往往過於麻煩，在很多情況下使用者並不會想要去使用。例如該定位系統需要時常換不同場地，如果已知參考點的部署過於複雜，使用者每次使用時會因為花很長一段時間去佈置並且紀錄各個參考點的位置而覺得並不人性化。因此，最理想的無線感測器網路定位系統是可以讓使用者任意放置感測器節點，該系統就能自行計算出節點間的相對位置，再進一步地定出其他待定位目標。
此論文提供一種能讓使用者隨機佈置感測器節點，不需要事先佈置任何位置已知的位置參考點，且這些節點會自行將它們自己的相對位置定出來。除此之外，此篇論文僅僅使用收到的訊號強度指標 (Received Signal Strength Indicator，簡稱RSSI)當作輸入訊號，節點本身並沒有任何事先已知的絕對座標或是相對座標。
此篇論文設計的中心概念：距離越遠的節點訊號越弱，距離越近的節點訊號越強。由於訊號強度和距離的關係式並不是固定的，因此並無法藉由訊號強度直接反算出距離來，但可以肯定的是藉由上述距離越遠則訊號越弱的概念，可以讓節點彼此測試和不同節點間的訊號強弱關係，藉此判定出不同節點之間的遠近關係。最後由遠近的相對關係可以完成整張不同節點的位置相對關係圖。此論文將會詳細介紹演算法和最後實驗的結果。

關鍵字

無限感測器網路 ； 零錨點 ； 自行定位 ； 隨機分布 ； 接收訊號好強度指標

並列摘要

In the past few years, localization technology has gained more and more attentions. Wireless sensor network is one of best solutions since nodes can be easily distributed around monitored environment and relay the required sensors information. Most methods require a pre-built infrastructure with anchor nodes, whose positions are known, to locate the blind nodes (unanchored nodes). These kinds of methods would take user much time to construct the system. For example, if user wants to move the locating system from one place to another, user should re-build all the anchor nodes due to the different environment. The most ideal method is to let user randomly distribute all the nodes and they will be located automatically.
In this thesis, a relative-localization identification of random deployed non-anchored nodes will be presented. Based on relative RSSI information, the system can identify which sensor nodes are placed in locations that are planned on the map. The method can let user put any nodes anywhere (random distributed), and the nodes will locate themselves without knowing the coordinate (absolute or relative) beforehand.
The main idea of this paper is: “Further nodes would get weaker signal strength, and vice versa.” Because the relationship between RSSI value and distance is not always fixed, the RSSI can not be transformed to distance directly. Nevertheless, we still can use the RSSI value to know which node is closer and which is further by the idea mentioned above. The distance relationship can draw the map which includes the relative locations of all the nodes. The algorithm and experimental verification of this method will all be detailed in this paper.

並列關鍵字

Wireless Sensor Network (WSN) ； Non-Anchor Node ； Self-Localization ； Random distributed ； Received Signal Strength Indicator(RSSI)

參考文獻

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