Yazar "Shakor, Abbas Qader" seçeneğine göre listele

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  • Küçük Resim
    Öğe
    Gözlem aralığının GPS, Glonass, Galileo ve BeiDou statik PPP üzerindeki etkisinin araştırılması
    (Necmettin Erbakan Üniversitesi Fen Bilimleri Enstitüsü, 2022) Shakor, Abbas Qader; Öğütcü, Salih Sermet
    GNSS gözlem aralıkları, belirli uygulamalar için düşük aralıktan yüksek aralığa (1-300 saniye gibi) ayarlanabilir. Bu çalışmada, 1-s, 5-s, 15-s ve 30-s örnekleme aralıklarının statik PPP (Precise Point Positioning)'nin yakınsama süresi ve konumlandırma doğruluğu üzerindeki etkisi 26 IGS-MGEX (International GNSS Service-Multi-GNSS Experiment) kullanılarak araştırılmıştır. İstasyonların 2020 yılında DOY (Day of Year) 95-116 arası üç haftalık dönem için 1-saniye gözlem aralıklı verileri seçilmiştir. Altı farklı GNSS sistemi -GPS, GLONASS, Galileo, BeiDou-2, BeiDou-3 ve çoklu-GNSS kullanılarak statik PPP sonuçları elde edilmiştir. Sonuçlar, daha düşük gözlem aralıklarının, her bir GNSS için PPP yakınsama süresini önemli ölçüde azalttığını göstermiştir. Bununla birlikte, daha düşük gözlem aralıklarının, her bir GNSS için PPP konum belirleme doğruluğunu biraz düşürdüğünü göstermiştir. Ayrıca uydu saati enterpolasyon hatasının yörünge enterpolasyon hatası ile karşılaştırıldığında daha düşük gözlem aralıkları için konum doğruluğunun azalmasında daha etken olduğu göstermektedir.
  • Küçük Resim Yok
    Öğe
    Investigating the effect of observation interval on GPS, GLONASS, Galileo and BeiDou static PPP
    (Selcuk Univ Press, 2022) Ogutcu, Sermet; Shakor, Abbas Qader; Farhan, Haitham Talib
    GNSS observation intervals can be tuned from low rate to high rates (such as 300 to 1 s) for the specific applications. In this study, the effect of sampling intervals of 1, 5, 15, and 30 s on the convergence time and positioning accuracy of static precise point positioning is investigated using high-rate data from 26 IGS (International GNSS Service)-MGEX (Multi-GNSS Experiment) stations over a three-week period in 2020. Six different GNSS constellations namely, GPS-only, GLONASS-only, Galileo-only, BeiDou-2-only, BeiDou-3-only, and multi-GNSS (GPS+GLONASS+Galileo+BeiDou-2+BeiDou-3) - are processed for static PPP. The results show that the use of higher rate of observation intervals significantly reduces the PPP convergence time for each GNSS constellation. Maximum improvements between 30 s and 1 s are found to be 55%, 60%, and 55% for north, east, and up components, respectively, for Galileo PPP. However, the results of positioning accuracy indicates that the use of higher rate of observation intervals slightly degrades the PPP converged positioning accuracy for each GNSS constellation except for BDS-3 and multi-GNSS PPP modes. The results demonstrate that the satellite clock interpolation error is mainly responsible for the degradation in accuracy at the higher rate of observation intervals compared with the orbit interpolation error.
  • Küçük Resim Yok
    Öğe
    Investigating the latest contribution of BeiDou-3 FOC to GPS/GLONASS/Galileo PPP
    (Taylor & Francis Ltd, 2023) Ogutcu, Sermet; Erkavas, Yuksel Kama; Shakor, Abbas Qader; Farhan, Haitham Talib
    In this study, the latest contribution of the BeiDou-3 FOC satellites to GPS/GLONASS/Galileo/BDS-2 combined static and kinematic precise point positioning (PPP) is investigated over a one-month period in 2021 considering the three different cut-off angles (7 degrees, 15 degrees, and 30 degrees). The results show that the contribution of BDS-3 to GPS/GLONASS/Galileo PPP is generally marginal for 7 degrees and 15 degrees cut-off angles. The largest BeiDou-3 contributions to static and kinematic positioning accuracy are found to be 9%, 6%, and 19% (for 3-h sessions with the 15 degrees cut-off angle) and 9%, 15%, and 8% (with the 30 degrees cut-off angle) for the north, east, and up components, respectively. The largest reductions in static and kinematic convergence time by adding BDS-3 to GPS/GLONASS/Galileo are found to be 13%, 10%, and 6% (for the 30 degrees cut-off angle) and 17%, 7%, and 6% (for the 30 degrees cut-off angle) for the north, east, and up components, respectively.
  • Küçük Resim Yok
    Öğe
    Performance investigation of Trimble RTX correction service with multi-GNSS constellation
    (Taylor & Francis Ltd, 2023) Atiz, Omer Faruk; Shakor, Abbas Qader; Ogutcu, Sermet; Alcay, Salih
    In the middle of 2011, Trimble introduced the RTX correction service to support RT-PPP applications. In this study, the performance of Trimble RTX correction service is investigated over a one-month period using five different GNSS constellations - namely, GPS-only, GPS + GLONASS, GPS + Galileo, GPS + GLONASS + Galileo, and GPS + GLONASS + Galileo + BeiDou. The results show that positioning accuracy and convergence time are significantly improved with the use of the multi-GNSS constellation compared with the GPS-only solution. The result of the converged positioning accuracy indicates that the GPS + GLONASS + Galileo + BeiDou combination improves the accuracy by 63%, 54%, and 60% for north, east, and up components, respectively, compared with the GPS-only solution. The mean convergence time is reduced by the GPS + GLONASS+ Galileo + BeiDou combination by 70%, 71%, and 38.6% compared with the GPS-only solution in the north, east, and up components, respectively. 1.2 (north), 1.5 (east), and 2.3 cm (up) root mean square errors (RMSEs) of converged positioning from the GPS + GLONASS + Galileo + BeiDou combination are computed.