| 摘要 |
<p>PROBLEM TO BE SOLVED: To measure a fine magnetic fluctuation of an extremely low frequency by arranging a plurality of region measuring pairs away from one another and calculating a correlation function for each pair so as to reduce the influence of city noise. SOLUTION: A plurality of region measuring pairs Ai (A1 to An), a collecting and analyzing center B and data transmission lines L1 to Ln are provided. The region pairs Ai each having a SQUID fluxmeter are arranged away from one another. Magnetic data is obtained by conversion with the 3-dimensional component detecting directions of the pickup coils of the respective SQUID fluxmeters coincided with one another. City noises are canceled by calculating the correlation function of each 3-dimensional component for each region pair Ai. An equation is solved based on magnetic data for each region pair Ai. Then, a position as a magnetism generating source, its magnetic direction and the intensity of magnetism are calculated.</p> |
