Patent ID: 6115668
Filing Date: 2000-09-05
Classification: G01C

Abstract:
A navigation apparatus comprising:a vertical movement detecting device for detecting a presence or absence of a movement in a vertical direction of a movable body associated with the movement of said movable body;a judging device for judging a position in the vertical direction of said movable body on the basis of the presence or absence of the movement in the vertical direction detected by said vertical movement detecting device; anda notifying device for notifying a present position of said movable body on the basis of the position in the vertical direction judged by said judging device,wherein said vertical movement detecting device further comprises(i) means for calculating Ga=Gc-Gb wherein Ga represents a component of a gravitational acceleration G in a moving direction of said movable body, Gb represents an acceleration in the moving direction obtained by differentiating a moving distance of said movable body twice with respect to time, and Gc represents an acceleration in the moving direction detected by an acceleration sensor of said movable body,(ii) means for calculating an inclination angle of said movable body .theta.=sin.sup.-1 (.vertline.Ga.vertline./.vertline.G.vertline.) by using the calculated Ga, and(iii) means for comparing the calculated inclination angle .theta. with a predetermined threshold value to thereby detect the presence or absence of the movement in the vertical direction.