Research And Design Of Underwater Video And Data Transmission System Based On Optical Cable

With the development of human society, the available resources on land is becoming less and less, which makes people think of the ocean as a new research object. The ocean, which accounts for over70%of earth’s surface, contains a large number of biological resources and mineral resources, especially in the deep sea and pelagic area, there are still many precious resources out the sight of the human. How to explore and develop those resources in a quick and reasonable way has became a great subject that must be solved by human beings.Exploring and developing deep-sea resources is different from that on land, people can not have a direct vision on the whole process of underwater operation, which makes people use deep-sea camera system to monitor that, so as to finish the underwater job accurately and quickly. For the deep-sea camera system, this paper designs and implements an underwater vedio and data transmission system based on optical cable, which mainly consists of fiber communication system, underwater embedded acquisition and control system and PC control interface on deck. The fiber communication system includes underwater fiber communication module and deck fiber communication module, it can monitor two channels video in real time, and also provides a transparent data channel for the underwater embedded acquisition and control system and the PC control interface. The underwater embedded acquisition and control system turn on or off underwater devices, such as cameras, lights, altimeter and so on, according to the downlink equipment control command sent by the PC control interface, it also needs to collect some status messages, including system voltage and towed body’s attitude, which will be sent to the PC control interface after being packed. The PC control interface can displays two channels video and monitoring data, transmits the underwater equipments’control command, stores and replays videos.The main work of this paper can be divided into four parts:the design of system program, hardware system, software system, and the whole system debugging.According to the needs of the deep-sea camera system, this thesis firstly makes system solutions for the underwater video and datatransmission system. Secondly, it introduces design principles and implementation of the fiber communication system and the underwater embedded acquisition and control system. The former’s hardware design includes video processing circuits, parallel-to-serial conversion circuit, Photoelectric conversion circuit, level switching circuit between PECL and LVDS, and so on; the latter contains underwater system power supply circuit, relay driver circuit, Angle measurement circuit, etc. Thirdly, the paper describes system software design, which includes the fiber communication system software design, the underwater embedded acquisition and control system software design and the PC control interface software design, the first one embodies the design of video and data frames’multiplex and demultiplex,8B/10encoding and decoding design, Manchester encoding and decoding design, and so on; the second one includes development of communication protocols, Analog signal acquisition and processing; the last one realizes the fucntion mentioned above. Lastly, the thesis describes the process of debugging the system.This paper designs and implements an underwater vedio and data transmission system based on optical cable for the deep-sea camera system. The deep-sea camera system has accomplished more than30stations operating on "HAI YANG LIU HAO" research vessel. In the process of operation, the system worked well. The research has achieved complete success.