Research And Development Of Expendable Current Profiler

Expendable ocean current profile survey technology has become one of the most widely used technologies in ocean current environment survey in the world.However,China's research in this aspect is in the early stage.This method could be used to research the movements of the ocean currents by measuring the induced electric field produced by the seawater movement cutting the earth magnetic field.Under the stable magnetic field,the extent of the ocean current induced electric field depends on the speed of the ocean current.Therefore,by measuring the induced electric field produced by the ocean current,we can understand the speed of the ocean current and research the features of the movements of the ocean currents.The expendable current profiler is designed based on this principle.At present,the only country that can master this technology is the United States which has monopolized such product with Japan and keep the technology from the non-alliance countries.The development of XCP technology is of great importance to the ocean scientific survey,military ocean dynamic environment monitoring and special ocean dynamic environment observation in China.In the thesis,the basic principle of the ocean current induced electric field is analyzed,and the technical plan for the expendable current profiler is put forward.According to the actual needs for the expendable current profiler,in the thesis,the author has discussed the development of the XCP ocean current electric field sensor,which could realize the AM modulation of the signals of the ocean current electric field through the self rotation of the XCP probe(16r/s),and could rapidly measure the weak ocean current electric field signals under the noisy background.In the thesis,the design discussed could realize the weak signal treatment circuit in the front of the XCP probe,which could supplement the hardware circuit of the cophase component of the ocean current electric field while screening and collecting the weak signals of the ocean current electric field,and could overcome the powerful interference of the induced electric field due to the lowering of the XCP probe.The SoPC technology is used in the XCP probe to rapidly measure and digitally treat the current electric field signals,the compass coil signals and the temperature information,and send the digital information to the floating cylinder end of the XCP through the UART protocol and the LVDS physical level data transmission method.The dynamic data transmission technology through the 2km and 0.1mm diameter varnished wire has been developed and the issues related to the digital data transmission between the XCP probe and the floating cylinder has been solved.In the thesis,the treatment method of XCP ocean current data has been researched based on the cophase component,orthogonal component and baseline data of the ocean current electric field signals and the compass coil signals collected with the XCP probe,to calculate the eastward and northward components of the relative speed of the ocean current.Three ocean tests have been conducted with the developed XCP to accumulate the XCP ocean test experiments,and the information about the XCP ocean current electric field and ocean temperature from the ocean surface to the depth of 1,000 meters in the South China Sea have been collected for the first time.