無人水下載具之無線雷射光通訊系統設計

本文提出一利用雷射光為資料傳輸媒介之水下載具無線通訊系統，目標在淺水區或是狹窄水域等不利於聲波傳輸的水下環境，用於操作者與水下載具之間的中短距離雙向溝通介面。硬體大體上分為兩個部分，固定通訊節點與水下載具節點，兩者皆使用PIN發光二極體做為接收器，不同處在於固定通訊結點使用高功率發光二極體(LED)作為發射器，後者使用結構光系統的線雷射，其包含一顆攝影機用於解析結構光與輔助導引水下載具結點的通訊連結，與658nm紅光線雷射發射器，傳輸開關鍵控調變的資料封包。並使用結合里得所羅門編碼與曼徹斯特編碼的改良型x-modem資料傳輸協議。里德索羅門碼提升資料封包對於資料錯誤的容錯能力；曼徹斯特碼降低傳輸訊號資料同步時所造成的位元錯誤。本文於一個大型水槽中，利用此通訊系統與使用視覺導航之自主式無人水下載具做通訊實驗，驗證此系統能以五千赫位元雙向通訊。

關鍵字

水下無線光通訊；水下載具；水下技術

並列摘要

An underwater wireless optical communication system that adopts laser and LED as the transmission medium is demonstrated. It serves as a short-distance and full-duplex wireless communication interface between underwater vehicles and humans in a shallow or narrow water environment where acoustic waves show unsatisfied communication performance. This system has two parts: static node and autonomous underwater vehicle node. They all adopt PIN photodiodes as optical receiver. The former uses the high power LED as its transmitter, and the latter was equipped a structured light system which includes a camera for structured light detection and the auxiliary navigation and control for the connection between the two nodes. These nodes connect each other with optical waves using On-Off Keying modulation method to carry data packets. The packets are the result of improved x-modem protocol that is constructed by Reed-Solomon code and Manchester code to reduce the probability of error bit happening during transmission. Finally, experiments were conducted in a water tank to prove the packet error rates (PER) can be satisfactory and the feasibility of a guidance system for communication.

並列關鍵字

underwater wireless optical communication ； underwater vehicle ； underwater technology

參考文獻

[1] Akyildiz, I.F., D. Pompili, and T. Melodia, “Underwater acoustic sensor networks: research challenges,” Ad hoc networks, 2005. 3(3): p. 257-279

[2] Robinson, B.S., et al “The Lunar Laser Communications Demonstration (LLCD),” Third IEEE International Conference on IEEE, SMC-IT, pp. 23-28, 2009.

[3] Kim, I.I., et al. “Wireless Optical Transmission of Fast Ethernet, FDDI, ATM, and ESCON Protocol Data Using the TerraLink Laser Communication System,” Optical Engineering, Vol. 37, No. 12, pp. 3143-3155, 1998.

[4] Baiden, G., Y. Bissiri, and A. Masoti, “Paving the Way for a Future Underwater Omni-directional Wireless Optical Communication Systems,” Ocean Engineering, Vol. 36, No.9-10, pp. 633-640, 2009.

[5] Hanson, F. and S. Radic, “High Bandwidth Underwater Optical Communication,” Applied Optics, Vol. 47, No. 2, pp. 277-283, 2008.

國際替代計量

無人水下載具之無線雷射光通訊系統設計

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