Distance factor learning device, distance factor learning method, distance factor learning program, recording medium recording said program, movement condition computing device, and present position computing device

Abstract

A signal acquisition sectionacquires, for example, a vehicle velocity pulse signal, which is generated from a vehicle velocity sensorin accordance with the movement of a vehicle that is a mobile body. A distance information acquisition sectionacquires distance information concerning the movement distance of the vehicle from a GPS receiver. A distance factor computing sectioncomputes a distance factor value based on the acquired vehicle velocity pulse signal and distance information. A change detection sectionthen compares this computed distance factor value and a distance factor reference value stored in a reference value storage sectionto detect a continuous change of the distance factor value. That is, change detection sectiondetects a change of tire outer diameter due to a change of the pneumatic pressure of the vehicle's tire or tire exchange, etc. When the change of tire outer diameter is detected by change detection section, a distance factor correction sectioncorrects the distance factor reference value speedily and appropriately.