Sea Non-contact Two-way Signal Transmission Technology Research

Deep Submersible Vehicle (DSV) is one of the most important vehicle for ocean exploration, by which scientists can reach the ocean floor. At the present time, the project of "7000 meters DSV" has been started in China and it is a great one. The object of this paper is the communication between DSV and its deployed tools.As the pressure is very high in seabed, the communication between the DSV and its deployed tools takes a contactless way. So the cable is out of question for safety consideration. The communication has some properties such as contactless, duplex, low baud rate, low power consumption. At the beginning of the designing, all of the underwater communication methods were studied. Undoubtedly, the overseas successful experience was used for reference. At last, Inductively Coupled Link (ICL) was been chosen from four options (acoustics, laser, electromagnetic wave, ICL) to realize the contactless communication. Based on the electromagnetic induction theory, ICL transmits signal by a pair of loops. In order to drive the loop, the modulation and demodulation theory was studied.Base on the theories above, the FSK (Frequency-Shifted-Keying) modulation mode circuits and OOK(On-Off-Keying) modulation mode circuits were designed. In order to make the ICL interface to be a communication standard, the parameter, loop and 10 is all the same. The properties of the communication are the rule of circuit designing. Low power consumption is an important factor because the deployed tools are powered by cells. In addition, the loops and encapsulation are important parts of ICL interface also.Fluid Sampler is one of the important tools for ocean crater exploration. Temperature is the guide of collection operation, So a circuit was developed to measure the temperature. At last, this circuit was integrated with the ICL interface. The whole circuit can collect, process and transport the temperature signal. The system experimentation proved that the OOK mode ICL interface can fill the communication demand between the DSV and deployed tools, and the circuit of thesampler can provide the temperature signal real timely.At last, the whole designing was summarized. Some pieces of advice were brought forward for further studying.