Abstract: A method and device for deriving a location. The method includes measuring, with a first sensor, movement as a function of time during a first period of time; deriving a typical movement area and a typical movement schedule using the measured movement; measuring, with the first sensor, movement as a function of time during a second period of time, wherein the second period of time corresponds to the first period of time; comparing the measured movement as a function of time during the second period of time with the derived typical movement area and the typical movement schedule; and initiating a second sensor to determine a current location if the measured movement as a function of time during the second period of time is not within the derived typical movement area or not aligned with the derived typical movement schedule based on the comparison.