Budtho, Jirapoom
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Preferred name
Budtho, Jirapoom
Alternative Name
Budtho, J.
Main Affiliation
Email
jirapoom.bu@kmitl.ac.th
3 results
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Item type:Publication, Clustering of Ionospheric Irregularities based on Spatiotemporal ROTI Keogram Images(2024-01-01); ; Tongkasem, NapatIonospheric irregularities associated with Equatorial plasma bubbles (EPB) can significantly impact navigation and communication systems. Therefore, their occurrences need to be studied and predicted. To solve the prediction problem, it is necessary to identify types of spatiotemporal characteristics as reference points for the predictive model. This work employs unsupervised machine learning algorithms to identify types of ionospheric irregularities due to EPB using the rate of total electron content index (ROTI) keograms. Two machine learning methods: two models, the Gaussian mixture model (GMM), and k-means, are considered. Comparative analysis is performed, and the optimal number of clusters is estimated using one classical, k-means and one additional - repeatability score, introduced in this work metric. The optimal GMM model successfully classifies three types of irregularity patterns offering valuable insights for the development of an effective EPB prediction model and enhancing our understanding of ionospheric behavior. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Analysis of Quiet Time Vertical Ionospheric Delay Gradients Around Suvarnabhumi Airport, Thailand(2018-09-01); ; Saito, S.Global Navigation Satellite System (GNSS) is vital to aircraft navigation at many phases of flight. To extend its use to the approach and landing phases, ground-based augmentation system is an important on-the-ground technology to reduce the positioning errors. However, nonuniform spatial ionospheric delays need to be assessed during ground-based augmentation system planning at each airport, particularly, in equatorial and low-latitude regions. In this work, we analyze the statistics of ionospheric delay gradients around Suvarnabhumi airport, Thailand. The ionospheric delay gradients are estimated using single-frequency code and carrier phase observation through the Kalman filter. To increase the success of the ratio test, the satellite elimination technique is then proposed. Based on the analysis between 2013 and 2016, we find that the background ionospheric delay gradients during equinox are higher than solstice, especially during September equinox 2013 when the gradients are about 9 mm/km. Moreover, the ionospheric delay gradients are more variable during daytime than nighttime. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Predicting Equatorial Ionospheric Total Electron Content Using the Transformer-based Model with Observations From Ground GNSS Receivers and COSMIC-2 Satellites(2025-01-01); ;