An integrity parameter, standard deviation of vertical ionospheric gradients (σvig), is broadcast to users of the Ground Based Augmentation Systems (GBAS) for the computation of protection levels (PL). The implementation of GBAS in South Korea would require an assessment of σvig  by analyzing data collected in South Korea on nominal days. Vertical ionospheric gradients are computed using the station-pair method and σvig is calculated using the sigma overbounding method. The analysis was carried out using GPS data observed in Korea for dates which are classified as “non-ionospheric storm” days. In this paper, we present the statistical results from ionospheric data analysis on nominal day in South Korea and provide a comparison with the integrity information implemented in the current CAT-I GBAS system to determine the feasibility of operating the system in South Korea. This study provides a better understanding of ionospheric behavior within South Korea under nominal conditions.

Keywords: statistical results, vertical ionospheric gradients (VIG), sigma overbounding, nominal day