A method for improved positioning of a mobile communication device, comprising the method steps of: a) providing position-related information in a plurality of first mobile communication devices, wherein the first mobile communication devices each have a receiving device (34, 37) which is adapted to receive positioning signals from a component (40, 50) of a navigation system; b) transmitting the position-related information from the plurality of first mobile communication devices to an evaluation device; c) determining, by the evaluation device, supplemental position information in the form of integrity information and/or correction data associated with a first point in time on the basis of the received position-related information, wherein the evaluation device performs a curve fitting calculation on the basis of position-related information received by the evaluation device from the plurality of first mobile communication devices; d) providing position information associated with the first point in time in a second mobile communication device, the first mobile communication devices and the second mobile communication device being distinct devices; e) transmitting the supplemental position information associated with the first point in time from the evaluation device to the second mobile communication device; f) determining, in the second mobile communication device, the integrity of the position information provided in step d) for the first point in time on the basis of the supplemental position information; and/or re-determining, in the second mobile communication device, position information for the first point in time (ta n) on the basis of the position information provided in step d) and associated with the first point in time (ta n) and the supplemental position information associated with the first point in time (ta n). a) providing position-related information in a plurality of first mobile communication devices, wherein the first mobile communication devices each have a receiving device (34, 37) which is adapted to receive positioning signals from a component (40, 50) of a navigation system; b) transmitting the position-related information from the plurality of first mobile communication devices to an evaluation device; c) determining, by the evaluation device, supplemental position information in the form of integrity information and/or correction data associated with a first point in time on the basis of the received position-related information, wherein the evaluation device performs a curve fitting calculation on the basis of position-related information received by the evaluation device from the plurality of first mobile communication devices; d) providing position information associated with the first point in time in a second mobile communication device, the first mobile communication devices and the second mobile communication device being distinct devices; e) transmitting the supplemental position information associated with the first point in time from the evaluation device to the second mobile communication device; f) determining, in the second mobile communication device, the integrity of the position information provided in step d) for the first point in time on the basis of the supplemental position information; and/or re-determining, in the second mobile communication device, position information for the first point in time (ta n) on the basis of the position information provided in step d) and associated with the first point in time (ta n) and the supplemental position information associated with the first point in time (ta n).