| 摘要 |
A generation section for root guide information 25 retrieves a plurality of information elements from an information data storage section 23 and creates root guide information. Then, a generation part for guide information data blocks 26 reorganizes the root information into a plurality of guide information data blocks including at least one information element from the root guide information. The guide information data blocks generated through reorganizing are sequentially transmitted from a radio communication unit 27 to an in-vehicle device 30. When it becomes impossible to execute route guidance using one type of guide information because of a breakdown in communication or the like, route guidance can still be executed by using guide information already received. |
