1. A method for entering a street name to determine an address of a destination for a navigation system, comprising the following steps of: displaying a screen for searching a street name, the screen including a street name input field for accepting a user's input of characters either by a full name or a base name of a street; distinguishing a non-base name element from a base name of a street name in the input character and displaying the non-base name element by a selected method on the screen; comparing the base name detected from the characters input by the user with entries in a base name database that stores base names of streets; retrieving base names from the base name database that match the base name detected from the characters input by the user and displaying a list of the retrieved base names; repeating the above steps of comparing and retrieving the base names every time when additional information is supplied by the user; and retrieving full names of streets from a full name database that stores full names of streets to determine a correct address of the destination.