A new method for mapping of vertical total electron content over Balkan Peninsula

A new method for mapping of total electron content (TEC) over Balkan Peninsula (35-46^o N, 20-29^o E) with a latitudinal and longitudinal step of 10 and a time resolution of one hour is developed. For this purpose 28 ground based GNSS stations are used. The presented method includes: (i) calculations of the slant TEC from the measured time delay of the signals; (ii) determinations of the instrumental biases of all GNSS stations, and (iii) computations of the instantaneous values of the vertical TEC for the respective coordinates. This procedure includes also a preliminary elimination of the invalid TEC values. The original element of this spatial mapping procedure is the use of the diurnal variability approximation in order to compensate the insufficient number of GNSS receiver stations particularly in some parts of the considered region. The obtained maps allow the examination of the meso-scale ionospheric anomalies with a spatial scale larger than 30 and time scale longer than 4 h. Key words: vertical total electron content mapping, receiver bias, satellite bias