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Author: search.filters.author.Keokhumcheng, ThanaponStart date: 2024

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    Total Electron Content Fluctuations and Their Implications for GPS Signal Delay over Thailand: Insights from Low Latitudes during the Ascending Phase of Solar Cycle 25
    (2026-05-04)
    Keokhumcheng, Thanapon
    ;
    Phothila, Prarinya
    ;
    Maichuen, Samatchaya
    ;
    Buakao, Nitipat
    ;
    Zhang, Jianfeng
    This research investigates how fluctuations in Total Electron Content (TEC) on the global positioning system (GPS) affect GPS performance in Thailand’s low latitude region during the ascending phase of solar activity 25<sup>th</sup>, utilizing data from 2023 to 2025. To capture TEC variations, five GPS monitoring stations were strategically deployed along a north-south transect across Thailand including Bangkok station, Chiang Mai station, KMITL Chumphon station, Nongbualumphu station, and Phuket station. TEC data collected from these stations were analyzed using statistical techniques with comparisons to IGS and IRI models to explore ionospheric dynamics and solar activity throughout the ascending phase of the cycle years, influencing TEC values and the time delay in the navigation system. The research reveals how solar-induced ionospheric changes influence TEC levels and cause time delays in GPS signals, which are critical factors for satellite navigation accuracy. These insights pave the way for enhancing GPS reliability and efficiency in low latitude regions, contributing to the development of more robust global navigation systems.
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    GNSS Receiver Bias Model for Near Real Time TEC Monitoring at Low Latitude, Thailand
    (2026-01-01)
    Kenpankho, Prasert
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    Maichuen, Samatchaya
    ;
    Phothila, Prarinya
    ;
    Zhang, Jianfeng
    ;
    Keokhumcheng, Thanapon
    This research proposes and investigates GNSS receiver bias modeling for near real time total electron content (TEC) monitoring across 16 multi-frequency GNSS stations in low latitude, Thailand, from 2022-2024. By applying a refined methodology based on Kenpankho et al. (2021) and integrating IONOLAB-BIAS for single station bias estimation, the research corrects for satellite and receiver inter-frequency biases to enhance TEC accuracy. Results show a consistent upward trend in TEC values, reflecting increased latitudes, seasonal ionospheric activity, and geomagnetic storms. Comparative analysis with the IRI 2020 model using correlation coefficients and RMSE reveals spatial and temporal variation, with near equatorial latitude stations showing strong alignment than upper low latitude stations. The results highlight the importance of localized GNSS-based TEC models for improving satellite positioning accuracy in equatorial regions and highlight the limitations of global models under dynamic ionospheric conditions.
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    The study of total electron content on ionosphere by using single frequency GPS receiver
    (2025-03-01)
    Keokhumcheng, Thanapon
    ;
    Kenpankho, Prasert
    In this research, we studied total electron content (TEC) on ionosphere by using single frequency from global positioning satellite system (GPS) satellite receiver. According to the ionospheric disturbance, ionospheric delay time on TEC is one of the most significant errors in GPS navigation systems. The positioning errors for GPS satellite systems from ionospheric delay depends on TEC over the region of interest as low latitude, Thailand. In research methodology, we proposed our ionospheric delay dataset on the period of the year 2004–2023 into the single frequency TEC method for finding GPS TEC. We investigated single frequency GPS TEC in three different stations, Bangkok, Chiang Mai, and Chumphon. Each station was installed the single and dual frequency GPS receivers for receiving the GPS signals over Thailand region. We investigated and compared single frequency GPS TEC results with dual frequency GPS TEC, International GNSS Service TEC (IGS TEC), and International Reference Ionosphere TEC (IRI TEC) in the year 2023. As the results, TEC using the single frequency GPS receiver is significantly statistical to be use for the study TEC on ionosphere over low latitude, Thailand.
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    Exploring Ionospheric Disturbances Using GNSS: A STEM-Based Investigation of the 2024 Extreme Geomagnetic Storm
    (2025-01-01)
    Pansong, Chollada
    ;
    Buakao, Nitipat
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    Keokhumcheng, Thanapon
    ;
    Phothila, Pharinya
    ;
    Intamas, Patcharin
    This study investigates the effectiveness of a STEM-based instructional approach integrating GNSS satellite technology and ionospheric TEC (Total Electron Content) analysis during extreme geomagnetic storms. The objective was to enhance students' conceptual understanding, practical skills, and STEM-related attitudes through interdisciplinary learning activities. The SPACE model (Study, Plan, Analyze, Create, Evaluate) was applied as a pedagogical framework to guide students through real-world TEC anomaly detection using GPS RINEX data and computational tools. The integration of real satellite data and hands-on analysis enabled students to connect theoretical knowledge with real-world phenomena, deepening their engagement and inquiry-based thinking. Pre-and post-test results revealed statistically significant improvements, with scores increasing from a mean of 5 1. 8 (S D = 7. 5 4) to 7 5. 0(S D= 7.42) (p < 0. 000001). Moreover, the STEM Attitude Questionnaire reflected strong positive perceptions, especially in STEM career motivation (x¯=4.20) and perceived value of STEM (x¯= 4.13). These findings highlight the model's potential to foster STEM readiness. Integrating GNSS-based TEC analysis into the STEM framework significantly enhanced students' academic outcomes, practical skills, and STEM attitudes.
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    Study of Ionospheric Total Electron Content over Thailand Using BeiDou Satellites
    (2025-01-01)
    Maichuen, Samatchaya
    ;
    Keokhumcheng, Thanapon
    ;
    Kenpankho, Prasert
    This study aims to analyze the Total Electron Content (TEC) in the ionosphere over Thailand using BeiDou satellite signals received by BG2s receivers, providing an alternative to the traditional use of GPS satellites for investigating TEC variations. Data were collected from January to March 2025 from six monitoring stations: Bangkok, Chiang Mai, Chumphon, Nong Bua Lam Phu, Phuket, and Ubon Ratchathani, respectively, covering the entire region of Thailand. The analysis revealed that Nong Bua Lamphu recorded the highest average at 77.94 TECU, followed by Chiang Mai with 73.55 TECU. Ubon Ratchathani had an average of 65.81 TECU, while Phuket recorded 59.54 TECU, closely followed by Bangkok with 59.22 TECU. Chumphon had the lowest average maximum value at 45.00 TECU, respectively. Additionally, training sessions were conducted for 20 participants of the Meteorological Department on using BG2s receivers to measure TEC from BeiDou satellites. The pre-training assessment showed that 6 participants, accounting for 30%, achieved scores above 80%. After the training, all participants, representing 100%, surpassed the 80% threshold. The results indicate an improvement in participants' knowledge from 30% to 100%, reflecting the success of the training program and demonstrating the potential for applying the BeiDou satellite system in future ionospheric TEC studies.
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    Space STEM Education Guide for Global Positioning System Total Electron Content (GPS TEC)
    (2024-01-01)
    Pansong, Chollada
    ;
    Keokhumcheng, Thanapon
    ;
    Sumniang, Patiphan
    ;
    Sittichai, Wishapol
    ;
    Huang, Canjie
    This research focuses on designing a Space Science teaching model using a Science, Technology, Engineering, and Mathematics (STEM) education approach, specifically applying satellite technology in the Global Navigation Satellite System (GNSS), with an emphasis on Global Positioning System (GPS) satellites. The goal is to propose a new model in STEM education in Space Science by teaching GPS Total Electron Content (GPS TEC) variations in the ionosphere layer resulting from environmental changes on Earth, known as Lithosphere-Atmosphere-Ionosphere Coupling (LAIC). The teaching model was designed, named SPACE (S: Studying the problem, P: Planning and carrying out investigations, A: Analyzing and interpreting data, C: Critical thinking, Creative thinking, Collaborating, Communicating, and E: Evaluating, and Summarizing), serves as a guide for instructional management steps. The model was evaluated by five experts with at least 10 years of experience in Space Science. The evaluation of the appropriateness of the model for use as a teaching guideline resulted in the highest level of suitability (x = 4.87, SD = 0.40).