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Abstract

This research aims to evaluate the performance of existing 1^st and 2^nd generation SBASs over Thailand region. In this study, a total of 40 GNSS Continuously Operating Reference Stations (CORS) in Thailand was analyzed with a 6-months period of data span. Preliminary results show that the positioning accuracy obtained from the single point positioning (SPP) technique are 1.90 m and 5.22 m in horizontal and vertical components (at 95% confidence level). With the GAGAN 1^st generation correction, the positioning accuracy are 2.12 m and 2.43 m in horizontal and vertical components. As for the BDSBAS 1^st generation correction, the positioning accuracy are 2.96 m and 4.38 m in horizontal and vertical components. In addition, the horizontal and vertical positioning accuracy obtained from the SPP with an ionosphere-free combination are 1.19 m and 2.74 m, while the horizontal and vertical positioning accuracy obtained from BDSBAS 2^nd generation correction are 2.25 m and 4.22 m. Therefore, there are no significant improvements in both vertical and horizontal positioning accuracy by applying SBASs in Thai region. These degraded results are mainly due to the fact that common satellites of SBAS’s provider have rapidly decreased outside of their ground tracking network. However, if the 2^nd generation Dual-Frequency Multi Constellation (DFMC) SBAS is implemented in Thai region using local ground tracking network, the positioning results are expected to be significantly improved. Many high accuracy applications such as air, land and sea navigations could be benefited from the implementation of 2^nd generation SBAS in Thai region.