Patent ID: 8340900
Filing Date: 2012-12-25
Classification: G01C

Abstract:
1. An alerting method of a navigation device comprising: (a) determining, by a receiving unit, a current location, receiving a destination inputted by a user, and displaying, by a displaying unit, at least a portion of corresponding map information; (b) planning, by a possible unit, possible routes by computing cost of each possible route, selecting, by the processing unit, the route with minimal cost as an optimized route among the possible routes, regarding, by the processing unit, other possible routes having a relatively higher cost as deviation routes; (c) computing, by the processing unit, a turning cost for each deviation route, wherein the turning cost represents cost difference between each deviation route and the optimized route respectively in an upcoming intersection, on which the possible routes are branched; (d) at a prompter location issuing, by a voice prompting unit, a voice guidance about how to follow the optimized route, wherein if the upcoming intersection has a turning cost greater than a warning threshold, then the upcoming intersection is a decision point, and additional alertness is issued before the upcoming intersection.