Disclosed is a navigation device comprising an apparatus that is used for mobile purposes and is provided with input and output means, a processor for processing an item of software, a navigation software for determining positions and calculating routes, and a first interface for transmitting data to and/or from the apparatus. Said navigation device is characterized in that the first interface is configured to read operational data and/or sensor data of at least one vehicle component into the apparatus via a second motor vehicle interface when the apparatus is in operation in a motor vehicle. Also disclosed is a data carrier with a navigation software for use in an apparatus embodied for mobile purposes. Said navigation software encompasses a software module that utilizes operational data of a vehicle or sensor data of sensors located in said vehicle to determine a position or a state of movement of the vehicle, the operational data being read in via an interface of the apparatus. The invention is characterized in that the accuracy of position determination is improved in navigation apparatuses provided for mobile use, particularly handheld computers, personal digital assistants, mobile radio telephones, and the like.