A Research Of An Underwater Connector For Submarine Seismic Observation

The ocean which covers 72% squares of the earth has been studied and used less than land and airspace which have been widely and maturely researched and applied in some degree.People begin researching ocean because of its great significance for people's living.By exploring the resource of ocean,observing dynamics of seabed,people can learn more about ocean.Aim to get further knowledge of earth and explore the inside structure and dynamics of the earth from all aspects and different perspectives,researchers start geophysical research on the ocean.especially in the area of seismic observation,it is very important for seismic observation and forecasting to grasp the real-time dynamic state of the seabed and get the ground motion of the seabed.There are essential devices and equipment applied in the ocean,ocean bottom seismograph is specially used for seismic observation in the ocean bottom.In recent years,the seismograph has been improved for better result.In addition,special devices which are used to equipment has been designed for those getting data more conveniently,efficiently and safely.A contactless under-water connector which is used to transmit power and data information for ocean bottom seismograph in the deep ocean will be discussed and designed at the article,so that the seismograph can work in better situation.The connector connects ocean bottom seismograph and submarine junction box which is connected in submarine observation network,then it provides long-term and continuously power for seismograph and exchanges real-time data information between seismograph and shore base station when it works at seabed.The connector is mainly used with electromagnetic coupling technology,by making a special electromagnetic coil to realize contactless transmission;then the design of power transmission circuit is completed by using D power amplifier and rectifier filter circuit;at the same time,signal transmission is completed by Manchester code baseband coding mode;finally,the transmission of power and signal and the control of the whole circuit are completed by using CPU and FPGA.At the present,most of seismographs use connected under-water contactors,the connectors require very high seal technology,what's more,most contactless connectors having been designed are almost applied for high-power instruments,and they transmit data information are in a certain range of distance.Therefore,existed contactless underwater contactors are not suited to ocean bottom seismographs which are low-power and short distance signal transmission devices.Thus the contactor designed at this article is specially to solve above problems.it is simple,reliable,safe and cheap and can be used more widely.Furthermore,with the feature of transmitting electric power and digital information in contactless situation,the connector is not only used for submarine seismograph but also may be applied for underground seismograph.avoids the lightning overvoltage being transmitted directly to the instrument through the wire,thus preventing the downhole seismometer from being damaged by lightning strike,and solving the important problem of lightning strike for the downhole seismometer.