To highly accurately detect the position based on position information transmitted from mobile equipment such as a portable telephone terminal.
A position detector 1 transmits the request of the position information to respective portable telephone terminals 2 capable of communicating with a GPS 3 by using the GPS 3. At the time of receiving the request, the portable telephone terminal 2 obtains its position information from the GPS 3 and transmits it to the position detector 1 together with transmission time information. The position detector 1 calculates the distance from the position detector 1 to the portable telephone terminal 2 based on the transmission and reception time (transmission time information and reception time information) received from the portable telephone terminal 2, prepares a circle or a sphere whose center is the position information of the portable telephone terminal 2 based on the result and the position information, calculates the intersection with the sphere as its own position, maps its calculated position on a map and thus detects its own present position.
| JPH0972751A | 1997-03-18 | |||
| JP2000102060A | 2000-04-07 | |||
| JP2002152798A | 2002-05-24 | |||
| JP2002359866A | 2002-12-13 | |||
| JP2002351905A | 2002-12-06 | |||
| JP2002291026A | 2002-10-04 | |||
| JPH1051840A | 1998-02-20 | |||
| JPH11505078A | 1999-05-11 |
Keiko Hada
Sanmei Takeuchi
Hiroto Yamachi
Sumiko Ohara