Patent ID: 7495580

Claim:
An apparatus for finding a parked vehicle, comprising: a portable unit with a pressure sensor that produces signals for evaluation by an evaluation and control unit in order to determine a current air pressure as a determined air pressure, with the evaluation and control unit evaluating the determined air pressure in order to determine altitude, and storing a first air pressure value as a reference value at a predeterminable first time, which reference value represents an instantaneous altitude of a geographic position of the parked vehicle, with the evaluation and control unit estimating a height difference between a current geographic position of the portable unit and the geographic position of the parked vehicle at a second time, or continuously from a pressure difference between the determined current air pressure value and the reference value, wherein, at the second time, when the portable unit communicates with a vehicle-end unit, the portable unit uses a pressure value obtained from the vehicle-end unit at the second time to estimate the height difference, and when the portable unit cannot communicate with the vehicle-end unit, the portable unit uses the reference value to estimate the height difference.