Patent ID: 8392108
Filing Date: 2013-03-05
Classification: G01C,G01S

Abstract:
1. An apparatus for improving reference data stored in a reference data base, comprising measured coordinates of a geographical reference position and a reference measurement packet allocated to the reference position, which comprises a reference transmitter identification determined at the geographical reference position and electromagnetic signal characteristics of a radio transmitter receivable at the reference position at a reference time, comprising: a processor implemented to match the measured coordinates approximating actual coordinates of the geographical reference position to coordinates of map objects of a geographical map to acquire improved coordinates more closely corresponding to the actual coordinates of the geographical reference position than the measured coordinates, and to replace, in the reference measurement packet stored in the reference data base, the measured coordinates of the geographical reference position by the improved coordinates; wherein the reference data base is used in determining a current geographical position by comparing a currently measured one of the electromagnetic signal characteristic of the radio transmitter to one of the electromagnetic signal characteristics of the radio transmitter in the reference measurement packet.