Performance improvement of the GAGAN satellite-based augmentation system based on local ionospheric delay estimation in Thailand

Abstract Satellite-Based Augmentation System (SBAS) is essential to support aircraft navigation. L1 SBAS operates on the frequency (1575.42 MHz) and currently still of interest since all GNSS satellites receivers do not fully additional frequencies such as L5 (1176.45 MHz). Although Global Positioning (GPS) aided Geo Augmented Navigation (GAGAN) available, performances are degraded due discrepancies ionospheric correction over Thailand surrounding areas. Hence, in this work, we propose a new method based geometry-free delay estimation with single (L1) reference station requirement. The local delays estimated proposed observed GPS GAGAN data Thailand. Then corrections obtained from delays. analysis shows that using corrections, positioning errors reduced both quiet days locally disturbed 2019. More reductions found September December than other months. In addition, perform preliminary availability assessment two critical phases flights. for APV-I LPV-200 categories improved up 57% 53%, respectively, comparison baseline IGP correction.