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Author: search.filters.author.Rungraengwajiake, SarawootSubject: search.filters.subject.Ionosphere

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    The GBAS protection levels and availability during ionospheric irregularity occurrence
    (2016-09-06)
    Limjumroonrat, Chayanan
    ;
    Rungraengwajiake, Sarawoot
    ;
    Supnihi, Pornchai
    ;
    Supanunt, Wisanu
    ;
    Siansawasdi, Nattapong
    The next generation aeronautical navigation system utilizes the Global navigation satellite system (GNSS) based equipment to aid aircrafts during approaching and landing. The Ground-based augmentation system (GBAS) broadcasts the augmentation information to the aircrafts in order to compensate for the GNSS signal-in-space errors and provides the accuracy, integrity, continuity and availability of system. The protection level is a parameter in the Standards and Recommended Practices (SARPs) from the International Civil Aviation Organization (ICAO) GBAS standard which validates the availability of system. The ICAO SARPs's algorithms are applied in this paper to compute the GBAS protection levels. We use the GNSS data recorded at the Suvarnnahumi international airport (AERO) in 2014. The results show statistics of days with ionospheric irregularity in 2014 as well as the protection levels during ionospheric irregularity occurrences. The average of the availability in March (equinox) is 99.30% and July (solstice) is 99.93% at the altitude of 100 feet. But the average availability of September (equinox) is 99.98%. So, that will be another reason that reduce the availability unless the ionospheric irregularity.
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    Loss-of-lock statistics from the GPS receiver near Suvarnabhumi airport, Thailand
    (2011-10-03)
    Le Hoai, Phong Pham
    ;
    Rungraengwajiake, Sarawoot
    ;
    Supnithi, Pornchai
    Loss-of-lock (LOL) statistics are important to the study of the ionosphere and the availability of the GPS/GNSS technology. The LOL data of the GPS, for instance, together with the spread-F and the rate of TEC change index (ROTI) are often used to the study of plasma bubble occurrence in the low and equatorial latitudes. In our work, we collected the data from the GPS receiver near Suvarnabhumi airport, Thailand, in 2010 and investigated the LOL statistics during this time. The number of proposed parameters including the probability of visible GPS satellites with LOL, and the number of usable GPS satellites are used to evaluate the LOL statistics. A comparison of the probability of LOL on both GPS frequency carriers indicates that the L<inf>2</inf> frequency is more susceptible to the LOL events than L<inf>1</inf> frequency. The results also show that the dense LOL occurrence is related to high fluctuation ROTI. The inversely correlation between elevation angles and number of visible GPS satellites with LOL is obtained as well. © 2011 IEEE.