| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy of calculation of a position with the use of a Kalman filter process. SOLUTION: A detection value adaptation range of an acceleration sensor 71 in a sensor section 70 is respectively set with respect to a movability and abilities of inconstancy and stoppage of a movable body having a mobile phone 1 held or mounted therein, and the detection value adaptation range about the movability is set to the widest, thereby a membership function for determining stoppage of the movable body is set. It is determined whether or not the movable body is in a stopping state by a fuzzy estimation operation with the use of the membership function. A value of an observation error covariance matrix "R" that is an error parameter in the event of performing a position calculation operation with the use of a Kalman filter and a value of a system noise matrix "Q" are changed in accordance with whether or not it is determined that the movable body is in the stopping state. The position of the movable body calculated out by a position calculation process with the use of a least-square method is corrected by a position calculation process with the use of the Kalman filter so as to determine an output position. COPYRIGHT: (C)2010,JPO&INPIT |
