The induced electric current caused by the motion of water across the earth s magnetic field generates the ocean background magnetic field.

To the problem of the low precision of common magnetometers caused by the influence of the background magnetic field,a new fluxgate gradiometer which is based on the technique of the three-tip fluxgate and the structure-type of two sensors is developed.

The research in IR image simulation about flight scene and ocean scene was scattered in recent year.

Firstly,the development of marine magnetic & gravity surveying technology is briefly reviewed.

Based on the practice of marine magnetic and gravity spatial database construction,a process and goal are introduced in data collation and constructing spatial database,and some techniques are analyzed.

Based on characteristics of the marine magnetic and gravity data such as multi-sources,heterogeneity and massive quantity,specialty on spatial database construction practice,objective and procedure of data collation and constructing are introduced in this paper,some key techniques about datum transfer,generalization,implied information extraction,analysis are researched.

It is very important that how to calculate the seismo geomagnetic background field,and study the anomaly variation of geomagnetic field,or geomagnetic residual field and secular variation field.