| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable navigation system utilized at a location at which GPS radio waves are less likely to be received, and improving the accuracy in position detection. SOLUTION: At least three magnetic field generating sources 4a-4c for generating AC magnetic fields having mutually different frequencies are disposed at predetermined positions. The AC magnetic fields are detected, by using a triaxial magnetic sensor 3a mounted to a portable terminal 2 and are resolved at each frequency. The strength of the AC magnetic field is calculated at each frequency. Distances from the portable terminal 2 to the magnetic field generating sources are calculated from the strength values. A position of the portable terminal 2 is identified. A travel start position of a user 6 can be correctly identified, even at a location at which the GPS radio waves are less likely to be received. When the user 6 moves, the current position of the user 6 is identified by an autonomous navigation. COPYRIGHT: (C)2011,JPO&INPIT |
