| 摘要 |
<P>PROBLEM TO BE SOLVED: To determine the arrival to a destination with high accuracy while maintaining a simple apparatus configuration. <P>SOLUTION: The arrival determination method calculates a first distance L(T<SB>1</SB>) between its own terminal and a destination at a prescribed time, a second distance L(T<SB>2</SB>) between its own terminal and the destination after a lapse of a prescribed time from the prescribed time, and a difference ΔL of the distances on the basis of a position P of the destination, a position P<SB>1</SB>(T<SB>1</SB>) of its own terminal at the prescribed time obtained by measurement, and a position P<SB>2</SB>(T<SB>2</SB>) of its own terminal after a lapse of a prescribed time from the prescribed time. Since a distance difference change ratio obtained by the difference ΔL/second distance L(T<SB>2</SB>) increases as the terminal approaches the destination, the method determines the arrival to the destination when the ratio exceeds a prescribed threshold value. Since this invention determines the arrival to the destination on the basis of not merely the distance up to the destination but the ratio of the difference ΔL to the first distance L(T<SB>1</SB>) or the second distance L(T<SB>2</SB>), a change in the ratio with respect to the elapsed time in the vicinity of the destination becomes greater and then this method can determine the arrival to the destination with higher accuracy. <P>COPYRIGHT: (C)2004,JPO |
