Navigation system and navigation method

A navigation system having a function of alerting the driver to potential wrong way driving comprises means 102 for determining a position of a vehicle 300, means 107 for calculating a driving route of the vehicle 300, means 108 for determining a driving maneuver in accordance with the predetermined driving route 305, means 104, 105, 110, 111 for outputting indications relating to the determined driving maneuver to a driver of the vehicle 300, and means 109 for alerting the driver to potential wrong way driving including means 201 for detecting a potential wrong way driving situation and means 202, 104, 105, 110, 111 for outputting an indication relating to the potential wrong way driving situation to the driver.