Research On Information Acquisition And Wireless Optical Transmission Technology Of Underwater Sensor Networks

The ocean area on the earth accounts for more than twice the land area,and is rich in fishery organisms,minerals,oil and gas,etc.With the increasing frequency of human marine activities,the research and development towards the ocean has attracted more and more scholars' attention.Both the acquisition of underwater physical information and the underwater communication are essential to marine activities for human.On the one hand,people's research on underwater sensor network information collection is mainly focusing on sensor nodes' localization and deployment in recent years.However,the design of the information collection module is rarely involved.On the other hand,underwater information transmission is mainly realized by underwater acoustic communication.Despite the long transmission distance of underwater acoustic communication,its long time-delay and small bandwidth make it difficult to reach a communication rate above Mbps.On the contrary,wireless optical communication has become a current research hotspot due to its large bandwidth,high rate,and extremely small delay.Therefore,this thesis mainly conducted an in-depth study on the underwater sensor information acquisition module as well as the underwater wireless optical communication,and mainly completed the following work.(1)The optical characteristics of seawater are studied,and the attenuation characteristics of the underwater wireless optical communication channel are simulated and analyzed based on the Monte Carlo model.Different types of seawater channels are simulated in the laboratory,underwater wireless LD and LED communication transmitter modules are designed and developed,underwater communication systems are built and their system performance are tested.A two-way communication system based on the LD optical communication machine and the Ethernet module is built to realize the underwater wireless optical transmission of actual services such as voice,video and files.(2)The underwater sensor information acquisition function based on the ARM platform is realized.The DS18B20 temperature sensor and OV5640 camera are used to collect underwater temperature information and image information.At the same time,the FATFS file system module is transplanted,and the collected data is named in sequence and then written into the SD card to achieve the storage function of the collected information.(3)The designed and developed underwater wireless optical communication module is cascaded with the underwater sensor information acquisition module based on the Ethernet conversion circuit,and the functional test is performed.The host computer is written using Qt as a server and ARM as a TCP client,so as to realize the collection,storage and wireless optical transmission of underwater environment information.An experimental system is built in the laboratory to simulate the marine environment and perform functional verification.