PORTABLE TERMINAL, PROGRAM, AND METHOD FOR DETERMINING ADVANCE DIRECTION OF PEDESTRIAN, USING GEOMAGNETIC SENSOR AND ACCELERATION SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a portable terminal, etc. capable of determining as accurately as possible an advance direction of a pedestrian having the portable terminal in hand, using an acceleration sensor and a geomagnetic sensor.;SOLUTION: The portable terminal possessed by the pedestrian includes the 3-axis acceleration sensor, the 3-axis geomagnetic sensor, and an advance direction determination means for determining the advance direction of the pedestrian from geomagnetic data. The advance direction determination means includes a normal vector calculation means for calculating a normal vector at a cone base on which a group of geomagnetic vectors generated by arm swing is distributed, out of acceleration data according to a lapse of time, a cone base approximation means for calculating the cone base out of the geomagnetic data and the normal vector, a cone height calculation means for calculating a height h of the cone, and a direction angle calculation means for calculating a direction angle θ against a north-south direction from the height h. The direction angle calculation means uses an angle I formed by geomagnetism and a gravitational direction to calculate the direction angle θ by a formula: θ= arcsin (h/sin I).;COPYRIGHT: (C)2010,JPO&INPIT