Apparatus, systems, and methods are disclosed relating to a position determination system for a motor vehicle for ascertaining whether the motor vehicle is located in an area covered by a ceiling element of a structure, comprising: a receiver unit, which is designed to receive navigation signals of a plurality of satellites of one or more global navigation satellite systems and to detect a change in signal strength, over time, of the respective navigation signals. An evaluation unit ascertains lines of sight from the motor vehicle to the respective satellites from which navigation signals were received, evaluates the change in signal strength, over time, of the respective navigation signals relative to the respective ascertained line of sight, and ascertains that the motor vehicle is entering the covered area by correlating a driving motion of the motor vehicle with the respective lines of sight.