Research On The Technologies Of Deep-sea Geomagnetic Survey

The magnetometric technology is used to be applied to delineation of seabed rock mass, zoning of petrographic province, deduce of structural configuration and position of the terrene. Recently, with the development of some magnetometric devices such as deep-sea magnetometer, exploration of deep-see geomagnetic field has attracted more and more attention, especially in the fields of the deep-sea resources investigation and ocean geological exploration,seismomagnetic precursor information. Seabed stratum is comprised of the stratum with different lithologies and containing minerals, which have different magneto conductivity and magnetic susceptibility and thereby result of different magnetic density. By measuring of the seabed geomagnetic field intensity, the geomagnetic field abnormality can be detected and thus the mineral distribution and geologic structure components can be determined with reasonable data process and analysis. This is the basic magnetic exploration approach, and also the main object of geomagnetic field exploration. This thesis focus on investigation and design magnetometer system, which is based on giant magnetoresistance effect and has high sensitivity,Besides, the data obtained from the system are also analyzed and regulated in order to achieve the object for the real time exploration of the deep-sea geomagnetic field variation.This paper is mainly divided into following subsections:1. In the first part, the deep-sea geomagnetism exploration techniques are introduced first, The state-of-art and tendency of the deep-sea geomagnetism exploration techniques in domestic country and abroad are concluded and summarized. And the working principles of magnetometer for ocean applications are described.2. This paper analyses the designning of the deep-seamagnetic field measurement instruments system, mainly comprising of the analysis of the principle of GMR sensors, selecting and characteristic analysis of the sensors, error analysis and calibrating of the three-component GMR sensors.And it makes a detailed description and analysis on the part of the circuit function ;3. This paper decscribes the designning of electronic system of the magnetometer. The hareware is basing on the MSP430 microcongtroller which is introducted in this article. It designs a high-precision data acquisition circuit, power supply circuit, processor peripheral circuit. And then it gives the attention and experience of the circuit designning;4. This paper introduces software design of the system, and describes the whole system software designing processes. It makes a specific introduce for AD7714 conversion, data processing, storage, SD card read-write protocol , the PC interface and the serial communication. And it makes a detailed describe of software code designning.5.Finally, this paper carrys out the the geomagnetic field bservation experiments of the magnetometer system in the lab, withing tidying and detailed analysising of the data.Experiments verify the magnetometer system is basically meeting the subject of the indicators required and the design target. At last the paper makes a summary of the whole working and points out the place that can be further improved and then forsees the application prospect of the magnetometer system.