Comparison of different ionospheric correction methods for single-frequency positioning

Abstract

In Global Navigation Satellite Systems (GNSS) using L band frequencies, the ionosphere causes signal delays that correspond with link related range errors of up to 100 meters. For dualfrequency receivers this error can be corrected by a linear combination of L1 and L2 measurements. Contrary, single-frequency users need additional information for mitigating the ionospheric error which is proportional to the Total Electron Content (TEC) of the ionosphere. This information can be provided by TEC models or by TEC maps deduced from corresponding GNSS measurements. In this study we discuss and compare different methods for mitigating the ionospheric error for single-frequency GPS users on position domain. The focus is on the comparison of positioning quality using the Klobuchar model, the global Neustrelitz TEC Model (NTCM-GL) and TEC maps both provided via the ionosphere data service SWACI (http://swaciweb.dlr.de) in near real-time. For this purpose, data from different locations covering several days are investigated, including periods of quiet and disturbed ionospheric conditions. In applying the NTCM-GL based corrections instead of Klobuchar, positioning accuracy improvements up to several meters have been found for the European region in dependence on the ionospheric conditions.