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Author: search.filters.author.Budtho, JirapoomSubject: search.filters.subject.Ionosphere

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    Compatibility of Low-Cost GNSS Receivers for Total Electron Content (TEC) Analysis
    (2025-01-01)
    Rana, Bhim Bahadur
    ;
    Supnithi, Pornchai
    ;
    Myint, Lin M.M.
    ;
    Tongkasem, Napat
    ;
    Budtho, Jirapoom
    Although the geodetic GNSS receivers are highly precise, they are inaccessible to every user, especially in remote areas. Therefore, this work aimed to find the reasons that bolster the low-cost GNSS receivers to be used with high resolution over a wide area, instead of geodetic in space weather studies. A comparative analysis was conducted between a low-cost Ublox ZED-F9P GNSS receiver and a geodetic Novatel Propak6 GNSS receiver, focusing on ionospheric parameters such as slant total electron content (STEC), vertical total electron content (VTEC), and the number of satellites tracked using the Global Positioning System (GPS). Additionally, VTEC values were compared with the GIM model. Both receivers exhibited a similar pattern of TEC, with the R2 value of 0.9734 and the root mean square error of 3.4583. The number of satellites tracked by both receivers during the observed periods was also found to be similar. Moreover, the VTEC results obtained from the low-cost GNSS receiver showed compatibility with the GIM model, demonstrating the reliability of the low-cost receiver in comparison to the geodetic GNSS receiver.
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    Study on Effect of Equatorial Plasma Bubble over Real-Time Kinematic Positioning in Bangkok Thailand
    (2022-01-01)
    Thu, Phyo C.
    ;
    Supnithi, Pornchai
    ;
    Myint, Lin Min Min
    ;
    Budtho, Jirapoom
    ;
    Saito, Susumu
    Equatorial plasma bubbles (EPBs) depict local ionospheric irregularity in low-latitude regions which can spread to mid-latitude regions. In this work, we analyzed the effects of the EPBs on the performance of real-time kinematic (RTK) positioning at the short, medium, and long baselines in Bangkok, Thailand. We used the kinematic positioning mode provided by a free and open-source software (FOSS) package called RTKLIB to analyze the positioning errors. It is found that the positioning errors are higher during the disturbance periods and more severe in the long baseline case.
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    Nominal ionospheric delay gradient estimation at Suvarnabhumi airport, Thailand
    (2017-10-19)
    Budtho, Jirapoom
    ;
    Supnithi, Pornchai
    ;
    Saekow, Apitep
    ;
    Saito, Susumu
    Ground-Based Augmentation System (GBAS) allows high-precision aircraft landing based on Global Navigation Satellite System (GNSS) at large airports. However, non-uniform spatial ionospheric delay needs to be determined. In this work, we compute the nominal ionospheric delay gradients around Suvarnabhumi airport, Thailand. The utilized techniques involve Kalman filter and LAMBDA method. Based on the measurements on DOY 043 of 2015, we found that the ionospheric delay gradients are less than 20 mm/km. With the improved ambiguity ratio test to obtain higher success rate than previous works, the standard deviation σ<inf>VIC</inf> is 5.27 mm/km.