POSITIONING SYSTEM AND METHOD OF POSITION DETECTING

摘要

A body-insertable apparatus has a resonance circuit for emitting a resonance magnetic field by being guided by a drive magnetic field received from the outside. An external device has: a drive coil driving unit for outputting a drive signal having a predetermined frequency; a drive coil for receiving the output drive signal and generating the drive magnetic field in a detection space; a sense coil for detecting the resonance magnetic field and outputting a detection signal; a position deriving unit for deriving position information of the resonance circuit by using the detection signal; a current detecting unit for detecting a current amplitude value of the drive signal input to the drive coil; and a drive magnetic field generation control unit for calculating an amplitude value of a drive signal which is output from the drive coil driving unit by using the current amplitude value, detecting the degree of stability indicating whether a sharp change occurs in the drive magnetic field on the basis of the calculated amplitude value, and controlling the position deriving unit on the basis of the detected degree of stability in the drive magnetic field detected.