GNSS-Based Detection of Polar Patches with Relative STEC Values - The Impact of Elevation Cut-off Angle

Nowadays the observations of Global Navigation Satellite Systems (GNSS) are considered as a reliable source of information on irregularities in the ionosphere. This contribution is aimed at evaluation of GNSS-based patch detection for different elevation mask. The extraction of patch signatures from geometry-free GNSS observables is performed with iterative fitting of 4- degree polynomial corresponding to the background slant total electron content (STEC) variations. For the testing purpose we selected two days: 9th and 15th March 2012. In order to obtain the point maps of relative STEC values, the data from a few tens of stations located at northern high latitudes were processed. The derived results confirmed that the proposed indicator allows the efficient detection of polar patches. However, the full view of their convection is limited by land mass configuration. The application of low elevation mask ensures better coverage of analysed area by GNSS data.