An in-vehicle navigation system includes a navigation device that further includes a receiving unit configured to receive information, a storage unit configured to store the received information, and a guidance unit. The navigation system further includes: a battery voltage detector; a temperature sensor; and a control device. The control device includes: a determination unit and a start-up control unit configured to periodically start the navigation device while the vehicle's engine is off, or cancel start-up of the navigation device based upon the detected battery voltage, a predetermined voltage level, and current and/or predicted temperatures.