在無線感測網路的環境，感測器的位置資訊在很多感測網路的機制與應用非常重要。但是無線感測網路的特色之一就是沒有固定的網路架構。隨機佈建於網路中的感測器並不會知道自己的位置。因此我們需要一些方法讓感測器能知道自己的位置。全球定位系統是很常見的一種定位手法。但是一般而言感測器有低成本的訴求，所以讓感測器搭配衛星定位系統是不理想的。因此有很多無線感測網路的定位方法被提出試圖解決。這些定位方法的主要目的之一就是要降低感測器成本，並達一定的定位精確度。另外，安全性的議題在無線感測網路中是非常重要的。但是大部分的定位方法都假設網路環境是處於安全的狀況下，並沒有考慮當惡意攻擊產生時該如何應對。本論文提出了一個安全的無線感測網路定位方法。除了讓感測器能準確的定位之外，我們同時也針對安全性的問題做了全面性的考量。我們的方法能夠抵擋許多針對無線感測網路定位的惡意攻擊，例如蟲洞攻擊等等。另外，因為感測器的訴求是低成本的裝置，所以許多資源如電力、記憶體容量和計算能力等有許多限制。所以在讓感測器的負荷降低的同時，並且還能提升整體網路的效能與定位精確度，也是我們的目標之一。

In wireless sensor networks, location information of sensor nodes is very important. However, in a self-configurable wireless sensor network, the randomly deployed sensor nodes cannot know their own locations a priori. Localization methods are needed to allow sensors to determine their locations. Global position system (GPS) is a widely used localization technique, but it is not suitable for sensor nodes, since sensor nodes are low-cost and hardware-limited devices. Therefore, many studies of localization method for wireless sensor networks have been proposed. Security issues are also very important in wireless sensor networks. Yet, studies have mostly assumed that they locate sensors in a trusted environment. These methods are in fact vulnerable to malicious attacks. In this paper, we propose a secure localization scheme, which is not only able to locate sensors with high accuracy, but also to fully solve the security problem. Our scheme is robust against several known attacks, such as Wormhole attack and Sybil attack. Since sensor nodes are low-cost and hardware-limited, one of our goals is to improve the performance of the entire network by reducing the overhead of sensor nodes, such as energy and storage.

目錄	I
圖目錄	III
表目錄	IV
第一章 緒論	1
第二章 相關研究工作	5
第三章 我們的方法	7
3.1 符號	7
3.2 網路架構與假設	7
3.3 安全的定位方法	12
3.4方法細節說明	16
第四章 分析與討論	23
4.1 安全性分析	23
4.2 感測器的傳輸負荷	28
4.3 感測器的儲存量負荷	30
第五章 模擬	31
5.1 平均定位誤差	31
5.2 成功定位比例	35
第六章 結論與未來研究工作	39
參考文獻	40
附錄－英文論文稿	43
圖目錄
圖一: 定位器示意圖	9
圖二: 整體架構示意圖	11
圖三: 方法流程圖	13
圖四: 蟲洞攻擊示意圖	24
圖五: 平均一個感測器所接收到的定位器數量	29
圖六: 平均定位誤差與定位器總量的模擬結果	32
圖七: 平均定位誤差與接收到定位器數量的模擬結果	34
圖八: 成功定位的感測器比例與定位器總量的關係(100×100平方公尺)	36
圖九: 成功定位的感測器比例與定位器總量的關係(200×200平方公尺)	37
表目錄
表一: 符號表	8
表二: 傳輸負荷比較	28
表三: 儲存量比較	30
表四: 模擬參數.	31

1.	Paramvir Bahl; Venkata N. Padmanabhan, “RADER: an in-building RF-based user location and tracking system,” Nineteenth Annual Joint Conference of the IEEE Computer and Communications Societies, vol.2, pp. 775-84
2.	Srdjan Capkun and Jean-Pierre Hubaux, “Secure Positioning in Wireless Sensor Networks,” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 24, NO. 2, FERURARY 2006, pp. 221-232.
3.	John Douceur, “The Sybil Attack,”In: 1st International Workshop on Peer-to-Peer System (IPTPS'02). Springer, 2002.
4.	Wenlian Du, Lei Fang, Ning Peng, “LAD: localization anomaly detection for wireless sensor networks,” Journal of Parallel and Distributed Computing (JPDC). Volume 66, Issue 7, July 2006, pp. 874-886.
5.	Jeffrey Hightower, Roy Want, and Gaetano Borriello, “SpotON: An indoor 3D location sensing technology based on RF signal strength,” UW CSE 00-02-02, University of Washington, Department of Computer Science and Engineering, Seattle, WA, Feb. 2000.
6.	Yih-Chun Hu, Adrian Perrig, and David Johnson, "Packet Leashes: A Defense against Wormhole Attacks in Wireless Networks," Proceedings of IEEE INFOCOM, San Francisco, CA, USA, April 2003, pp. 1976-1986.
7. 	Loukas Lazos and Radha Poovendran, “HiRLoc: High-Resolution Localization for                    Wireless Sensor Networks,” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 24, NO. 2, FERURARY 2006, pp. 233-246.
8.	Zang Li, Wade Trappe, Yanyong Zhang, and Badri Nath, “Robust statistical methods for securing wireless localization in sensor networks,” Proceedings of The Fourth International Symposium on Information Processing in sensor networks (IPSN '05), April 2005. pp. 91-98.
9.	Donggang Liu, Peng Ning, and Wenliang Kevin Du, “Attack-resistant location estimation in sensor networks,” Proceedings of The Fourth International Symposium on Information Processing in sensor networks (IPSN '05), April 2005. pp. 99-106.
10.	Asis Nasipuri, Kai L, “A directionality based location discovery scheme for wireless sensor networks,” WSNA 2002, pp. 105-111.
11.	Dragoş Niculescu and Badri Nath, "Ad Hoc Positioning System (APS) using AoA," Twenty-Second Annual Joint Conference of the IEEE Computer and Communications Societies, Vol. 3, 2003, pp. 1734-1743.
12.	Nissanka B. Priyantha, Anit Chakraborty, and Hari Balakrishnan, “The Cricket location-support system,” Proceedings of the 6th annual international conference on Mobile computing and networking, 2000, pp. 32-43.
13.	Naveen Sastry, Umesh Shankar, and David Wagner, “Secure verification of Location Claims,” ACM Workshop on Wireless Security (WiSe 2003), September 19, 2003, pp. 1-10.
14.	Kuo-Feng Ssu, Chia-Ho Ou, and Hewifin Christine Jiau, “Localization With Mobile Anchor Points in Wireless Sensor Networks,” IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 54, NO. 3, MAY 2005, pp. 1187-1197.
15.	Ariel Tamches, Barton P. Miller, ”Dynamic fine-grained localization in Ad-Hoc networks of sensors,” Proceedings of the 7th annual international conference on Mobile computing and networking, 2001, pp. 166-179. 
16.	Sheng-Shih Wang, Kuei-Ping Shish, and Chih-Yung Chang, “Distributed direction-based localization in wireless sensor networks,” Computer Communications, Volume 30, Issue 6, MARCH 2007,	pp.1424-1439.
17.	Bernhard Hofmann-Wellenhof, Herbert Lichtenegger, James Collins,.”Global Positioning System: Theory and Practicr,” 4th ed.New York: Springer-Verlag, 1997.
18.	Yan-Chao Zhang, Wei Liu, Yu-Guang Fang, and Da-Peng Wu, “Secure Localization and Authentication in Ultra-wideband Sensor Networks,” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 24, NO. 4, APRIL 2006, pp. 829-835.