Publication: Investigation of ionospheric effects on ground based augmentation systems at low latitude region
Date
2024-09-01
Authors
Rajwant Singh, Brelveenraj Kaur
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Abstract
Space-based technologies such as the Global Navigation Satellite Systems (GNSS) are playing an increasingly important role in aviation navigation due to the
increasing demand for long-haul air travel. This encouraged airports to deploy Ground Based Augmentation System (GBAS) replacing the Instrument Landing System (ILS) which resulted in reduced delays and disruptions for travellers. Low latitudes and equatorial regions, such as Malaysia are more likely to experience ionospheric disturbances caused by solar activity and geomagnetic storms, which disturb the GNSS signals. The performance of the GNSS is subjected to risk as the integrity of the GBAS between the ground receiver and the aircraft deteriorates. This study analyse ionospheric scintillation and Total Electron Content (TEC) effects on the GBAS receivers installed at KLIA. The data collected was during solar minimum which reflected towards the GBAS in KLIA not experiencing any anomaly events that could disrupt the GPS receiver's signal during equinox months. The amplitude scintillation, S4 index values were found within (0.2 < S4< 0.5), indicating weak or negligible scintillation. The GBAS receivers consistently show of spikes of S4 data at precise times across the months, suspected due to nearby interference rather than active scintillation events. The TEC values vary from a low in the early hours of the day to a
diurnal maximum between 15:00 LT and 18:00 LT before falling to a minimum in the afternoon. The TEC were particularly higher in September and March corresponding to the months of equinox. This paper investigates the ionospheric disturbance in the low latitude region and ideas for improving GBAS receiver performance for future developments.