| 摘要 |
PROBLEM TO BE SOLVED: To detect whether or not there is a magnetic object, such as an automobile, in the vicinity with high sensitivity and even in a movement. SOLUTION: A microprocessor 60 reads in a first detection signal from a first fluxgate type magnetic detection element 10-1 and reads in a second detection signal from a second fluxgate type magnetic detection element 10-2, and determines that there are no magnetic objects in the vicinity if changes in the detection signals are the same or substantially the same or determines that there is a magnetic object in the vicinity if changes in the detection signals are different in magnitude by a predetermined value or larger. Whether or not there is a magnetic object, such as an automobile, in the vicinity can thus be detected with high sensitivity (practical sensitivity range of 10 m or longer) and even in a movement. COPYRIGHT: (C)2006,JPO&NCIPI
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