Navigation apparatus, method for map matching performed in the navigation apparatus, and computer-readable medium storing a program for executing the method

A method for map matching performed in a navigation apparatus mounted on a vehicle, the navigation apparatus being capable of displaying a vehicle's location on a digital road map on a screen and matching the vehicle's location on a road to its position on the digital road map, the method comprising the steps of:

• (a) detecting a current position of the vehicle;
• (b) taking images of a road on which the vehicle is traveling;
• (c) detecting and watching lane markers on the road to obtain detection results, the detection and watching being performed by processing the images taken at the step (b);
• (d) judging whether or not a fork is located ahead of the current position of the vehicle based on route/map data stored in a database of the navigation apparatus, the route/map data including at least information of forks in roads, in which the fork information of each of the forks is stored in association with at least two predetermined conditions relating to features of the fork;
• (e) retrieving the fork information of the fork from the route/map data in the database, the retrieval being made in a case where it is judged at the step (d) that a fork is located ahead of the current position of the vehicle;
• (f) judging whether or not the vehicle has entered a specific area that is set with respect to the fork;
• (g) determining the road on which the vehicle is traveling after passing the fork or on which the vehicle is going to travel after passing the fork, the determination being made based on the detection results and the predetermined conditions relating to the fork;
• and
• (h) correcting the vehicle's position displayed on the digital road map based on the determined road to match the vehicle's location on the road to its position on the digital road map.

A computer-readable medium which stores a program for executing a method for map matching performed in a navigation apparatus mounted on a vehicle, the navigation apparatus being capable of displaying a vehicle's location on a digital road map on a screen and matching the vehicle's location on a road to its position on the digital road map, the method comprising the steps of:

• (a) detecting a current position of the vehicle;
• (b) taking images of a road on which the vehicle is traveling;
• (c) detecting and watching lane markers on the road to obtain detection results, the detection and watching being performed by processing the images taken at the step (b);
• (d) judging whether or not a fork is located ahead of the current position of the vehicle based on route/map data stored in a database of the navigation apparatus, the route/map data including at least information of forks in roads, in which the fork information of each of the forks is stored in association with at least two predetermined conditions relating to features of the fork;
• (e) retrieving the fork information of the fork from the route/map data in the database, the retrieval being made in a case where it is judged at the step (d) that a fork is located ahead of the current position of the vehicle;
• (f) judging whether or not the vehicle has entered a specific area that is set with respect to the fork;
• (g) determining the road on which the vehicle is traveling after passing the fork or on which the vehicle is going to travel after passing the fork, the determination being made based on the detection results and the predetermined conditions relating to the fork;
• and
• (h) correcting the vehicle's position displayed on the digital road map based on the determined road to match the vehicle's location on the road to its position on the digital road map.